openapi: 3.0.3
info:
  title: Words Categories Definitions API
  version: 1.0.0
  description: Words API is a RESTful English-language API that provides definitions, synonyms, antonyms, related words, syllables, pronunciation (IPA), rhymes, frequency, and hierarchical lexical relationships (typeOf, hasTypes, partOf, hasParts, memberOf, similarTo, also, entails, inCategory, inRegion, pertainsTo, etc.) for more than 150,000 English words. Authentication is handled via the RapidAPI marketplace using the X-RapidAPI-Key and X-RapidAPI-Host headers.
  contact:
    name: Words API Support
    email: support@wordsapi.com
    url: https://www.wordsapi.com/
  license:
    name: Words API Terms of Service
    url: https://www.wordsapi.com/
  x-generated-from: documentation
  x-last-validated: '2026-05-30'
servers:
- url: https://wordsapiv1.p.rapidapi.com
  description: Words API production endpoint, served through the RapidAPI gateway.
security:
- RapidApiKey: []
tags:
- name: Definitions
  description: Words API Sense-level Definitions Grouped by Part of Speech.
paths:
  /words/{word}/definitions:
    get:
      tags:
      - Definitions
      operationId: getDefinitions
      summary: Get Word Definitions
      description: Returns every documented definition for the word, grouped by part of speech.
      parameters:
      - $ref: '#/components/parameters/Word'
      responses:
        '200':
          description: Definitions returned.
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/DefinitionsResponse'
        '404':
          $ref: '#/components/responses/NotFound'
      x-microcks-operation:
        delay: 0
        dispatcher: FALLBACK
components:
  schemas:
    DefinitionEntry:
      type: object
      description: One definition with its grammatical category.
      properties:
        definition:
          type: string
          description: Definition text.
          example: fruit with red or yellow or green skin and sweet to tart crisp whitish flesh
        partOfSpeech:
          type: string
          description: Grammatical category.
          example: noun
    DefinitionsResponse:
      type: object
      description: Response from GET /words/{word}/definitions.
      properties:
        word:
          type: string
          example: apple
        definitions:
          type: array
          items:
            $ref: '#/components/schemas/DefinitionEntry'
    Error:
      type: object
      description: Error response body returned by Words API when a request fails.
      properties:
        success:
          type: boolean
          description: Always false for error responses.
          example: false
        message:
          type: string
          description: Human-readable description of the error.
          example: word not found
      required:
      - message
  parameters:
    Word:
      name: word
      in: path
      required: true
      description: The English word to look up.
      schema:
        type: string
      example: apple
  responses:
    NotFound:
      description: Word not found in the Words API dictionary.
      content:
        application/json:
          schema:
            $ref: '#/components/schemas/Error'
  securitySchemes:
    RapidApiKey:
      type: apiKey
      in: header
      name: X-RapidAPI-Key
      description: RapidAPI subscription key. The X-RapidAPI-Host header (wordsapiv1.p.rapidapi.com) is also required.