name: Datadog APM Vocabulary
description: >-
  Shared vocabulary of terms used across Datadog APM for distributed tracing,
  service catalog, and service level objectives.
terms:
  - term: Trace
    definition: >-
      A directed acyclic graph of spans representing a single end-to-end
      request through a distributed system.
  - term: Span
    definition: >-
      A timed operation within a trace, recording resource, service,
      duration, and key metadata.
  - term: Service
    definition: >-
      A logical application or component instrumented by Datadog APM and
      registered in the service catalog.
  - term: Service Definition
    definition: >-
      A schema-versioned descriptor of a service including ownership,
      contacts, links, and metadata managed via the service definition API.
  - term: Resource
    definition: >-
      A specific endpoint, query, or method within a service that spans are
      grouped under for analysis.
  - term: SLO
    definition: >-
      A service level objective measuring the reliability of a service
      against a target over a time window.
  - term: SLI
    definition: >-
      A service level indicator metric that backs an SLO, derived from
      monitors or events.
  - term: Tag
    definition: >-
      A key-value pair attached to traces, spans, services, and SLOs for
      filtering and grouping.
  - term: Site
    definition: >-
      A regional Datadog deployment such as US1, EU, US3, or US5 that
      serves the API at a region-specific hostname.
  - term: Trace Search Query
    definition: >-
      A query expression used to filter traces and spans by service,
      resource, status, and tags.
  - term: Continuous Profiler
    definition: >-
      Datadog's always-on profiling system that captures CPU, memory, and
      I/O performance data for running services.
  - term: Trace Metric
    definition: >-
      A pre-aggregated metric derived from traces such as request count,
      latency percentiles, or error rate.