# Travel Metasearch Glossary

Technical glossary for travel metasearch and distribution terminology.

## Pages

- [ARI](https://metasearch.com.tr/en/glossary/ari.md): Distribution of hotel availability, rates and inventory state. Reliable ARI depends on change detection, idempotency and reconciliation.
- [Availability](https://metasearch.com.tr/en/glossary/availability.md): Whether an offer is actually sellable for a given date, occupancy and product context. A price alone does not guarantee availability.
- [Inventory](https://metasearch.com.tr/en/glossary/inventory.md): Sellable room, seat or vehicle capacity. Inventory must be interpreted together with restrictions, allotments and stop-sell rules.
- [Rate Plan](https://metasearch.com.tr/en/glossary/rate-plan.md): Commercial rules defining cancellation, meals, payment, eligibility and promotions. Multiple rate plans can exist for the same room type.
- [Room Type](https://metasearch.com.tr/en/glossary/room-type.md): The accommodation product class within a hotel. Stable room identity and occupancy semantics matter more than display names during mapping.
- [Hotel List](https://metasearch.com.tr/en/glossary/hotel-list.md): Static property master data supplied to a distribution platform. Stable IDs, address, geo and active state are foundational to matching quality.
- [POI Feed](https://metasearch.com.tr/en/glossary/poi-feed.md): A feed model describing physical properties or businesses with location and metadata. It can serve as the property-identity layer in hotel aggregation.
- [Property Mapping](https://metasearch.com.tr/en/glossary/property-mapping.md): Determining whether records from different sources represent the same physical property. Bad mapping can attach an otherwise correct rate to the wrong hotel.
- [Canonical ID](https://metasearch.com.tr/en/glossary/canonical-id.md): A stable internal identifier that survives supplier or channel changes. Channel-specific IDs should map into the canonical model through adapters.
- [Price Coverage](https://metasearch.com.tr/en/glossary/price-coverage.md): The share of searchable hotel/date/occupancy or route/date contexts for which pricing is available. Drops can signal connectivity or inventory issues.
- [Price Accuracy](https://metasearch.com.tr/en/glossary/price-accuracy.md): Consistency between the displayed metasearch rate and downstream booking rate. Taxes, fees, currency and occupancy semantics often cause mismatches.
- [Rate Parity](https://metasearch.com.tr/en/glossary/rate-parity.md): Price alignment of genuinely comparable hotel offers across channels. Parity is misleading unless room, meal, cancellation and tax differences are normalized.
- [Total Price](https://metasearch.com.tr/en/glossary/total-price.md): The total mandatory amount payable by the traveler, including applicable taxes and fees. Nightly rate and total price are not interchangeable.
- [Base Rate](https://metasearch.com.tr/en/glossary/base-rate.md): The base price before taxes, mandatory fees or other components. Confusing it with total price creates price-accuracy problems.
- [Markup](https://metasearch.com.tr/en/glossary/markup.md): Commercial uplift applied over a supplier net rate. It may vary by market, channel, product or campaign and affects parity and ROAS analysis.
- [Commission](https://metasearch.com.tr/en/glossary/commission.md): Revenue share paid to a distribution channel, often based on booking value. Gross commission and post-cancellation net commission should be tracked separately.
- [CPC](https://metasearch.com.tr/en/glossary/cpc.md): Cost incurred per offer click. Efficiency should be read together with click-to-book conversion and net booking value, not CPC alone.
- [CPA](https://metasearch.com.tr/en/glossary/cpa.md): Cost per defined acquisition or booking. Attribution windows and cancellation policy materially affect interpretation.
- [CPS](https://metasearch.com.tr/en/glossary/cps.md): Cost tied to a completed sale. In travel, the sale definition may mean confirmed, stayed or non-cancelled booking.
- [ROAS](https://metasearch.com.tr/en/glossary/roas.md): Revenue generated relative to ad spend. Versions based on net revenue or margin can be more useful than gross booking value.
- [Look-to-Book](https://metasearch.com.tr/en/glossary/look-to-book.md): Ratio of searches or lookups to bookings. It is critical for supplier API capacity planning and cache strategy.
- [CTR](https://metasearch.com.tr/en/glossary/ctr.md): Share of impressions that generate a click. CTR alone is not quality and should be interpreted with downstream conversion.
- [Conversion Rate](https://metasearch.com.tr/en/glossary/conversion-rate.md): The booking rate from a defined funnel step. Its meaning changes depending on whether the denominator is search, detail view or provider click.
- [Attribution](https://metasearch.com.tr/en/glossary/attribution.md): Model assigning booking credit to clicks, sessions, campaigns or sources. Last-click attribution misses assisted influence in multi-touch travel journeys.
- [Assisted Conversion](https://metasearch.com.tr/en/glossary/assisted-conversion.md): A channel or interaction that contributes to booking without being the final click. It matters in journeys such as OTA research followed by direct booking.
- [Conversion Tracking](https://metasearch.com.tr/en/glossary/conversion-tracking.md): Measurement of bookings, cancellations and revenue after a click. Stable click IDs and reconciliation are essential to channel economics.
- [Reconciliation](https://metasearch.com.tr/en/glossary/reconciliation.md): Matching clicks, bookings, modifications, cancellations and payments across systems. It keeps performance reporting aligned with commercial reality.
- [Deep Link](https://metasearch.com.tr/en/glossary/deep-link.md): A URL that sends the traveler into booking with the selected product and search context. Dates, occupancy, currency and attribution should be preserved where possible.
- [Landing Page](https://metasearch.com.tr/en/glossary/landing-page.md): The provider or booking page opened after a metasearch click. HTTP 200 alone is insufficient; product and price context must also be preserved.
- [OTA](https://metasearch.com.tr/en/glossary/ota.md): An online travel intermediary that exposes inventory and often owns much of the booking transaction. The distinction from metasearch is largely about acquisition and transaction ownership.
- [Metasearch](https://metasearch.com.tr/en/glossary/metasearch.md): A distribution layer that normalizes and compares offers from multiple providers in one search context. Identity, freshness, ranking and handoff are core technical problems.
- [Travel Marketplace](https://metasearch.com.tr/en/glossary/travel-marketplace.md): A platform model combining multiple travel verticals, suppliers and transaction models in one consumer-facing retail surface. It may include comparison without being pure metasearch.
- [Tour Operator](https://metasearch.com.tr/en/glossary/tour-operator.md): A distribution role that contracts and combines accommodation, transport, transfers or other travel services into a packaged product.
- [Package Holiday](https://metasearch.com.tr/en/glossary/package-holiday.md): A bundled travel product combining at least two travel services in one package context. Component identity, package price and cancellation state need joint management.
- [Merchant of Record](https://metasearch.com.tr/en/glossary/merchant-of-record.md): The entity accepting customer payment through its merchant account and carrying primary payment-record, chargeback and refund responsibility.
- [Seller of Record](https://metasearch.com.tr/en/glossary/seller-of-record.md): The entity shown as seller in the customer contract and carrying the transaction's contractual seller identity. It does not have to be the Merchant of Record.
- [Reprice](https://metasearch.com.tr/en/glossary/reprice.md): Validation of a previously observed offer against current price, availability and commercial conditions closer to booking.
- [Supplier](https://metasearch.com.tr/en/glossary/supplier.md): A hotel, airline, wholesaler, GDS or other inventory source. Supplier contracts are evaluated through availability, rate semantics, latency and commercial terms.
- [Provider](https://metasearch.com.tr/en/glossary/provider.md): The party supplying an offer or completing the booking. Provider ranking can depend on reliability and conversion quality as well as price.
- [Feed](https://metasearch.com.tr/en/glossary/feed.md): Bulk or scheduled machine-readable data transfer between systems. Production feeds require schema discipline, versioning, idempotency, validation and observability.
- [Catalog](https://metasearch.com.tr/en/glossary/catalog.md): A normalized product/entity view built by an advertising or distribution platform from feeds. A correct source feed can still produce a bad catalog through mapping rules.
- [API](https://metasearch.com.tr/en/glossary/api.md): A request/response or action contract between systems. In travel, latency, rate limits, retry behavior and idempotency are part of the operational contract.
- [Pull Pricing](https://metasearch.com.tr/en/glossary/pull-pricing.md): Pricing model where the platform requests required rates at query time. Upstream latency and concurrency capacity become critical.
- [Changed Pricing](https://metasearch.com.tr/en/glossary/changed-pricing.md): Approach where the partner signals changed pricing so the platform refreshes relevant contexts. Change-detection quality drives stale-price risk.
- [Live Price](https://metasearch.com.tr/en/glossary/live-price.md): A current provider-backed price for high-intent search. It has different freshness expectations from an indicative price.
- [Indicative Price](https://metasearch.com.tr/en/glossary/indicative-price.md): An approximate or aggregated price signal used for flexible-date or destination discovery. Live repricing is needed closer to booking.
- [Freshness](https://metasearch.com.tr/en/glossary/freshness.md): How closely data reflects current source state. Different data domains require different TTL and freshness objectives.
- [Stale Price](https://metasearch.com.tr/en/glossary/stale-price.md): A rate that remains outdated in metasearch or cache after changing at the source. It creates post-click mismatch and conversion loss.
- [TTL](https://metasearch.com.tr/en/glossary/ttl.md): How long cached data can be used before refresh. TTL should reflect booking intent, supplier latency and change volatility.
- [Cache Hit Ratio](https://metasearch.com.tr/en/glossary/cache-hit-ratio.md): Share of requests served from cache rather than upstream calls. A high hit ratio is useful only when it does not increase stale data.
- [Latency Budget](https://metasearch.com.tr/en/glossary/latency-budget.md): The response-time allocation for each supplier or service in an end-to-end search. Timeouts and progressive results should be designed around it.
- [Circuit Breaker](https://metasearch.com.tr/en/glossary/circuit-breaker.md): A resilience pattern that temporarily stops calls to failing or slow upstream services. It limits search latency and cascading failures.
- [Idempotency](https://metasearch.com.tr/en/glossary/idempotency.md): The property that repeated updates or conversion events do not corrupt state. It is critical in feed retries and booking-event pipelines.
- [Backoff](https://metasearch.com.tr/en/glossary/backoff.md): A strategy that increases delay between retry attempts. It helps prevent retry storms during rate limits or upstream outages.
- [Itinerary](https://metasearch.com.tr/en/glossary/itinerary.md): A flight journey composed of legs and segments. Pricing options are commonly defined in itinerary-plus-agent context.
- [Leg](https://metasearch.com.tr/en/glossary/leg.md): An origin-to-destination direction within an itinerary, such as outbound or return. A leg may contain multiple segments.
- [Segment](https://metasearch.com.tr/en/glossary/segment.md): A physical flight operation between one departure and arrival. Marketing and operating carriers can differ.
- [Carrier](https://metasearch.com.tr/en/glossary/carrier.md): The airline marketing or operating a flight. Carrier identity should not be confused with booking-agent identity.
- [Agent](https://metasearch.com.tr/en/glossary/agent.md): The airline, OTA or provider selling a flight offer. The same itinerary can be sold by multiple agents with different prices and conditions.
- [Direct Booking](https://metasearch.com.tr/en/glossary/direct-booking.md): Booking completed through the supplier's own channel. Direct offers in metasearch need comparable semantics against OTA offers.
- [Booking Engine](https://metasearch.com.tr/en/glossary/booking-engine.md): System managing availability, rate, guest, payment and confirmation. Metasearch deep links should preserve the correct context into it.
- [CRS](https://metasearch.com.tr/en/glossary/crs.md): A system that centrally manages hotel inventory, rate plans, availability and reservations. It can act as an important source-of-truth layer between PMS, channel managers, booking engines and distribution channels.
- [PMS](https://metasearch.com.tr/en/glossary/pms.md): The core hotel operations system managing reservations, room assignments, check-in/out, folios and guest state.
- [Channel Manager](https://metasearch.com.tr/en/glossary/channel-manager.md): A distribution layer synchronizing hotel rates, availability and inventory across multiple OTAs and channels.
- [GDS](https://metasearch.com.tr/en/glossary/gds.md): A global reservation and distribution infrastructure connecting airline, hotel and other travel inventory to agencies and distribution ecosystems.
- [NDC](https://metasearch.com.tr/en/glossary/ndc.md): An IATA-defined messaging standard for modern API-based airline offer and order distribution.
- [Bedbank](https://metasearch.com.tr/en/glossary/bedbank.md): A B2B accommodation wholesaler that contracts hotel inventory and redistributes it to OTAs, tour operators and other resellers.
- [Wholesaler](https://metasearch.com.tr/en/glossary/wholesaler.md): A B2B intermediary that acquires travel inventory under contracted or net terms and resells it to other channels.
- [Merchant Model](https://metasearch.com.tr/en/glossary/merchant-model.md): A commercial model where the intermediary charges the traveler and settles a contracted or net amount with the supplier.
- [Agency Model](https://metasearch.com.tr/en/glossary/agency-model.md): A model where the traveler typically pays the supplier and the intermediary earns commission.
- [MinLOS](https://metasearch.com.tr/en/glossary/minlos.md): A restriction defining the minimum number of nights accepted for a given arrival/date/rate context.
- [MaxLOS](https://metasearch.com.tr/en/glossary/maxlos.md): The maximum stay length permitted for a rate or date context.
- [CTA](https://metasearch.com.tr/en/glossary/cta.md): A restriction preventing check-in on a specific date.
- [CTD](https://metasearch.com.tr/en/glossary/ctd.md): A restriction preventing check-out on a specific date.
- [Derived Rate](https://metasearch.com.tr/en/glossary/derived-rate.md): A rate whose price is derived from another rate plan using fixed or percentage adjustments.
- [Occupancy Pricing](https://metasearch.com.tr/en/glossary/occupancy-pricing.md): A pricing model where amounts vary by adult/child counts, child ages or room occupancy.
- [Offer Fingerprint](https://metasearch.com.tr/en/glossary/offer-fingerprint.md): A stable comparison identity representing offer semantics such as property/itinerary, occupancy, room/fare, meal, cancellation, eligibility and currency.
- [Price Observation](https://metasearch.com.tr/en/glossary/price-observation.md): A price observed for a specific query context and timestamp, stored with amount, currency, source, observedAt and freshness metadata.
- [Attribution Window](https://metasearch.com.tr/en/glossary/attribution-window.md): The period during which a click or interaction remains eligible for attribution to a downstream booking.
- [Conditional Rate](https://metasearch.com.tr/en/glossary/conditional-rate.md): A rate available only to users meeting membership, mobile, geography, loyalty or campaign conditions.
- [Stale-While-Revalidate](https://metasearch.com.tr/en/glossary/stale-while-revalidate.md): A caching pattern that serves recently cached data immediately while refreshing it in the background.
- [Bulkhead](https://metasearch.com.tr/en/glossary/bulkhead.md): A resilience pattern that isolates resources so one provider or workload failure does not cascade to others.
- [Rate Limit](https://metasearch.com.tr/en/glossary/rate-limit.md): The request or capacity quota accepted by an API provider within a time window.
- [Matured Booking](https://metasearch.com.tr/en/glossary/matured-booking.md): A booking considered commercially more settled after enough cancellation/refund exposure has passed.
- [Contribution Margin](https://metasearch.com.tr/en/glossary/contribution-margin.md): The economic contribution remaining after channel acquisition, commission, payment, servicing and relevant variable costs are deducted from revenue.
- [Offer](https://metasearch.com.tr/en/glossary/offer.md): A sellable commercial proposal combining itinerary/property, price, availability, seller and conditions. Offer identity should retain its source reference through repricing and booking.
- [Order](https://metasearch.com.tr/en/glossary/order.md): The commercial record that tracks product, traveler, payment and servicing state after purchase. In flight/NDC systems, an order is not the same thing as a PNR or ticket.
- [PNR](https://metasearch.com.tr/en/glossary/pnr.md): A reservation record containing passenger and itinerary information. A PNR can represent booking state but is not proof of ticket issuance or payment settlement.
- [Ticket](https://metasearch.com.tr/en/glossary/ticket.md): The document or electronic record representing the right to air transport. An order can be confirmed while ticket issuance is still pending.
- [Ticketing](https://metasearch.com.tr/en/glossary/ticketing.md): The lifecycle that turns a confirmed flight order into ticket document/coupon state and later manages void, exchange or refund operations.
- [Fare Family](https://metasearch.com.tr/en/glossary/fare-family.md): A branded flight product bundling baggage, seat, change/refund and ancillary rights. Normalizing only the numeric price can erase meaningful fare-family differences.
- [Ancillary](https://metasearch.com.tr/en/glossary/ancillary.md): An optional service added to the core travel product, such as baggage, seats, lounge access or priority. Its identity and eligibility should survive booking and servicing.
- [Servicing](https://metasearch.com.tr/en/glossary/servicing.md): The post-booking lifecycle covering changes, cancellations, reissues, refunds and support. Strong search/booking APIs do not compensate for weak servicing capabilities.
- [Fulfillment](https://metasearch.com.tr/en/glossary/fulfillment.md): Delivery of the purchased travel value as a ticket, voucher, confirmation or other usable entitlement.
- [Authorization](https://metasearch.com.tr/en/glossary/authorization.md): The payment step that approves or reserves a chargeable amount on a payment method. Successful authorization does not imply capture or booking confirmation.
- [Capture](https://metasearch.com.tr/en/glossary/capture.md): The act of collecting or submitting for settlement an amount that was previously authorized. Booking and payment should be tracked as separate state machines.
- [Void](https://metasearch.com.tr/en/glossary/void.md): A payment reversal performed before settlement completes. It differs from a refund, which returns value after a completed charge.
- [Refund](https://metasearch.com.tr/en/glossary/refund.md): A full or partial return of a completed payment to the customer. In travel, refund state should be reconciled across supplier, seller and PSP systems.
- [Webhook](https://metasearch.com.tr/en/glossary/webhook.md): A server-to-server HTTP callback that pushes state changes to another system. Delivery, ordering, retries and signature verification are part of the production contract.
- [Polling](https://metasearch.com.tr/en/glossary/polling.md): A method of discovering state changes by periodically querying an API instead of waiting for events. Poll interval, rate limits and eventual consistency should be designed together.
- [Saga](https://metasearch.com.tr/en/glossary/saga.md): A workflow pattern for multi-service operations that cannot fit into one ACID transaction, using steps and compensating actions. It is useful for distributed travel flows such as booking plus payment.
- [Compensation](https://metasearch.com.tr/en/glossary/compensation.md): A business action that reverses the effect of a completed step in a distributed workflow, such as voiding a payment authorization after booking failure.
- [Unknown Outcome](https://metasearch.com.tr/en/glossary/unknown-outcome.md): A state where a timeout or connection loss makes it unclear whether the upstream action completed. UNKNOWN should not be treated as FAILED without lookup or reconciliation.
- [Idempotency Key](https://metasearch.com.tr/en/glossary/idempotency-key.md): A stable request key used to prevent the same logical mutation from being applied twice on retry. It is critical for side-effecting operations such as booking, payment and order creation.
- [Agentic Commerce](https://metasearch.com.tr/en/glossary/agentic-commerce.md): A commerce model where an AI agent interacts with structured commerce systems for discovery, selection, checkout or transactions on a user's behalf. Authorization, auditability and deterministic transaction boundaries are core concerns.
- [MCP](https://metasearch.com.tr/en/glossary/mcp.md): An open protocol for AI applications to interact with tools, resources and context providers through a standard interface. It is not a commerce or payment protocol; it is a capability-access layer for agents.
- [A2A](https://metasearch.com.tr/en/glossary/a2a.md): An open protocol aimed at capability discovery, task delegation and interaction between independent agents. It addresses a different layer from MCP, which focuses on tool/resource access.
- [ACP](https://metasearch.com.tr/en/glossary/acp.md): An open commerce standard for merchant catalogs, checkout and agent-mediated purchasing. It lets agents transact through structured commerce contracts while merchants retain control of checkout and payment systems.
- [UCP](https://metasearch.com.tr/en/glossary/ucp.md): An open protocol for standardizing commerce interactions such as capability negotiation, checkout and order flows across platforms, businesses and payment providers.
- [AP2](https://metasearch.com.tr/en/glossary/ap2.md): An open payment-authorization protocol for proving user authority and transaction intent in agent-performed payments through verifiable mandates. It is not itself a commerce protocol; it focuses on the payment trust and authorization layer.
- [MPP](https://metasearch.com.tr/en/glossary/mpp.md): An open protocol standardizing machine and agent payments inside HTTP request flows through payment challenges, credentials and receipts. It is designed to be payment-method agnostic.
- [x402](https://metasearch.com.tr/en/glossary/x402.md): An open payment standard using HTTP 402 Payment Required so a client can receive payment requirements for a resource and retry the request with proof of payment.
- [Mandate](https://metasearch.com.tr/en/glossary/mandate.md): A structured authorization artifact proving which actions, amounts, merchants or conditions an agent is allowed to act within. In agentic payments it provides explicit authority instead of inferred intent.
- [Delegated Payment](https://metasearch.com.tr/en/glossary/delegated-payment.md): Secure delegation of payment credentials or spending authority into an agent/merchant flow with constraints such as amount, expiry and permitted use.
- [Human-in-the-Loop](https://metasearch.com.tr/en/glossary/human-in-the-loop.md): A control model where an agent workflow pauses for human approval, review or decision at a critical step. It can serve as an authority boundary for high-impact booking, payment or cancellation actions.