canonical: https://jentic.com/apis/dictionaryapi.dev/dictionaryapi # Dictionaryapi Free Dictionary API Jentic publishes the only available OpenAPI specification for Free Dictionary API, keeping it validated and agent-ready. The Free Dictionary API returns English word definitions, phonetic transcriptions, audio pronunciation links, parts of speech, synonyms, antonyms, and example sentences for any headword. A single lookup takes a language code and a word and responds with every matching sense grouped by meaning. It is free and open, requires no key, and is widely used to add inline definitions and pronunciation to reading, learning, and writing tools. ## For AI agents Look up the definition, phonetics, audio pronunciation, part of speech, synonyms, and antonyms of an English word in a single call. Returns structured JSON grouped by meaning, with no authentication required. ## Scope Does not handle translation, spelling correction, or text generation. Use for looking up English word definitions, phonetics, and synonyms only. ## Capabilities - Retrieve full definitions for an English word grouped by part of speech and meaning - Fetch phonetic transcriptions and audio pronunciation URLs for a headword - Pull synonyms and antonyms attached to each sense of a word - Return example sentences that illustrate how a word is used - Look up any headword by language code and word in one request ## Use cases ### Inline definitions for an AI writing assistant An AI writing or reading agent can define unfamiliar words on demand by calling the Free Dictionary API with a language code and the target word. The response returns each sense with its part of speech, phonetics, and example usage, so the agent can explain a term in context without a paid dictionary licence. Through Jentic the agent discovers the lookup operation by intent and calls it directly. Example prompt: Look up the word 'ubiquitous' for the English language code en and return its part of speech, phonetic spelling, and first definition ### Pronunciation for a language-learning app Language-learning tools use the Free Dictionary API to show learners how a word sounds. Each lookup returns phonetic transcriptions and links to audio pronunciation files where available, alongside the written definition, so an app can play the audio and display the meaning together. No account or key is required to start. Example prompt: Retrieve the phonetic text and audio URL for the word 'colonel' and confirm an audio file is present ### Thesaurus lookups inside a text editor A writing tool can offer synonyms and antonyms while a user drafts. The Free Dictionary API attaches synonym and antonym lists to individual senses of a word, letting the editor suggest alternatives that match the intended meaning rather than a flat word list. Definitions and examples come back in the same response for quick disambiguation. Example prompt: Get the synonyms and antonyms for the adjective sense of 'bright' and return up to five of each ## Key resources - **Definitions** — Look up definitions, phonetics, audio, synonyms, antonyms, and example sentences for a word by language code and headword ## Why Jentic - **Setup:** Wiring the Free Dictionary API by hand is light because it needs no key, but you still write the HTTP client, handle the language-code and word path, and parse the nested meaning and phonetics structure yourself. Through Jentic you install once, import the Free Dictionary API from the API Directory, and your agent calls the lookup with no credential to provision. - **Permission scoping:** The Free Dictionary API is read-only and exposes one lookup operation, so a rule can allow your agent that single definition lookup and nothing else. There are no write or delete operations, and the API carries no credential that could reach beyond reading public dictionary data. - **Credential handling:** The Free Dictionary API is public and uses no credential, so there is nothing for Jentic to store or inject. The calls your agent makes carry no secret into its prompt, logs, or context. - **Discovery method:** Agents search Jentic by intent such as 'define a word' or 'get a word's pronunciation', and Jentic returns the Free Dictionary lookup operation with its input schema so the agent calls the right endpoint without reading the reference docs. ## Related APIs - **Merriam-Webster Dictionary API** — Established dictionary and thesaurus data, key-gated, versus the free no-key Free Dictionary API. - **Oxford Dictionaries API** — Multilingual, licensed lexical data versus the English-only free lookup here. - **Wordnik API** — Adds word lists, real-world example sentences, and related words alongside core definitions. ## FAQ ### Why is there no official OpenAPI spec for Free Dictionary API? Free Dictionary API does not publish an OpenAPI specification. Jentic generates and maintains this spec so that AI agents and developers can call Free Dictionary API via structured tooling. It is validated against the live API and kept up to date. To run it on your own infrastructure, install Jentic One from its GitHub repo. ### What authentication does the Free Dictionary API use? The Free Dictionary API requires no authentication. Its OpenAPI spec declares no security scheme, so requests to the definitions endpoint are public and need no key or token. Because there is no credential, there is nothing to store, rotate, or expose when an agent calls it through Jentic. ### Can I get audio pronunciations with the Free Dictionary API? Yes. Each word lookup can return phonetic transcriptions and links to audio pronunciation files where the dataset has them, alongside the written definition and part of speech. An agent requests a word by language code and reads the phonetics and audio URL from the response. ### What are the rate limits for the Free Dictionary API? The OpenAPI spec does not specify rate limits for the Free Dictionary API. It is a free community service, so apply conservative client-side throttling and caching and check the project documentation at `https://dictionaryapi.dev` for current guidance. ### Can I limit what my agent is allowed to do with the Free Dictionary API? Yes. The Free Dictionary API exposes a single read-only lookup operation, so an agent connected through Jentic can only read word definitions and cannot change any data. You choose which operations it may call, and every call it makes is logged. ### Is there a Free Dictionary API MCP server? You don't need an MCP server to give your agent the Free Dictionary API. Jentic connects it directly from the API Directory: import it and your agent calls the definition lookup on demand, with no key to configure because the API is public. ### How do I look up a word with the Free Dictionary API through Jentic? Search Jentic for an intent like 'define a word', which returns the Free Dictionary lookup operation with its input schema: a language code such as en and the target word. Your agent sends the word and reads back the definitions, phonetics, and example sentences, with no credential to configure because the API is public.