Lexical Data API

The Oxford Dictionaries API is a single API that supports multiple language capabilities. This page describes how to use the API for retrieving structured lexical and linguistic metadata such as inflections, etymology and grammatical features, and usage labels.

Use the Lexical Data API capability when you need machine-readable information about word structure, form, and linguistic properties, rather than dictionary definitions or translations.

Endpoints overview

The Lexical Data API capability is implemented using the Words (or Entries), Inflections, and Translations endpoints. Lexical metadata is returned as part of the structured response from these endpoints.

What can you do with the Lexical Data API?

The Lexical Data API provides access to rich word-level linguistic features:

Inflections

Retrieve inflected and derived forms of a word (e.g. swim → swims, swimming, swam, swum).

In linguistics, an inflection is a change in the form of a word to express a grammatical function such as:

  • tense
  • mood
  • person
  • number
  • case
  • gender

For example:

  • a noun in the plural form (e.g. star → stars)
  • a verb conjugated to the past (e.g. give → gave)

Inflectional data is available across multiple endpoints:

  • Words, Entries and Translations
    Returns inflections as part of the structured lexical metadata.
  • Inflections
    Returns full inflection tables for a given lexical entry and lexical category.

Used for:

  • Morphological generation
  • Grammar tools
  • Input normalisation
  • Query expansion
Tip: For complete and exhaustive inflection tables, use the Inflections endpoint, which is the canonical source for morphological generation.
Element name(s) inflections
Languages / dialects available

Words (or Entries) endpoint: British English (en-gb), American English (en-us), French (fr), Hindi (hi), Latvian (lv), Romanian (ro), Spanish (es), Tamil (ta).

Inflections endpoint: British English (en-gb), American English (en-us), Hindi (hi), Latvian (lv), Spanish (es), Romanian (ro), Tamil (ta).

Translations endpoint: English (en) ⇆ Arabic (ar), German (de), Portuguese (pt), Russian (ru); English (en) → Spanish (es), Hindi (hi), Greek (el), Italian (it), Malay (ms), Marathi (mr); Hausa (ha) → English (en).
Example calls to the Oxford Dictionaries API

To get inflections for the word give using the Words endpoint, you can call:

GET https://od-api.oxforddictionaries.com/api/v2/words/en-gb?q=giveCopy

To get inflections for the word give using the Inflections endpoint, you can call:

GET https://od-api.oxforddictionaries.com/api/v2/inflections/en-gb/giveCopy

To get inflections for the word give in another language (e.g. Spanish) using the Translations endpoint, you can call:

GET https://od-api.oxforddictionaries.com/api/v2/translations/en/es/giveCopy

Etymologies

Access the etymological history of a word – its origin and historical development.

Available via:

  • the Words (or Entries) endpoints

Used for:

  • Language learning
  • Historical linguistics
  • Lexical research
Element name(s) etymologies
Languages / dialects available

Words (or Entries) endpoint: British English (en-gb), American English (en-us), Gujarati (gu), Hindi (hi), Romanian (ro), Spanish (es).

Translations: Available for Hindi (hi) → English (en).
Example calls to the Oxford Dictionaries API

To get the etymology of the word record, you can call:

GET https://od-api.oxforddictionaries.com/api/v2/words/en-gb?q=record&fields=etymologiesCopy
Tips If you'd only like to receive etymologies from the response, you can use the optional fields Query Parameter as demonstrated above.

Domains

Retrieve domain classifications that describe topical usage (e.g. Law, Botany or Military).

Available via:

  • the Words (or Entries) endpoint
  • the Translations endpoint

Used for:

  • tone and style tagging
  • writing and editing tools
  • educational platforms
Element name(s) domains
Languages / dialects available

Words (or Entries) endpoint: British English (en-gb), American English (en-us).

Translations endpoints: Domains label available for English (en) → German (de), Italian (it), Portuguese (pt), Georgian (ka).
Example calls to the Oxford Dictionaries API

To list the available domain labels in British English you could call:

GET https://od-api.oxforddictionaries.com/api/v2/domains/en-gbCopy

To see the domain labels for the word point on the Words endpoint, you could call:

GET https://od-api.oxforddictionaries.com/api/v2/words/en-gb?q=pointCopy

To see the information for the word point in one specific domain only (e.g. Cricket, Music or Ballet), you can specify this in the following way:

GET https://od-api.oxforddictionaries.com/api/v2/words/en-gb?q=point&domains=cricketCopy
Tips Other than domains, there are two other labels you can use for domain and subject labels in English monolingual endpoints: domainClasses for more domain class coverage, and semanticClasses for other related categories (e.g. State, Shape or Component).

Registers

Access register metadata that categorises how and where a word sense is typically used.

In linguistics, a register describes the stylistic, social or situational context of a word sense.

It can include:

  • Formality level (e.g. formal, informal)
  • Typical context of use (e.g. technical, literary)
  • Taboo or sensitivity (e.g. vulgar slang, offensive)

Registers are applied at the sense level, allowing you to distinguish between neutral, technical, informal or sensitive meanings of the same word.

Available via:

  • the Words (or Entries) endpoint
  • the Translations endpoint

Used for:

  • tone and style tagging
  • content moderation and filtering
  • educational and learner tools
  • writing and editing guidance
  • context-aware language applications
Element name(s) registers
Languages / dialects available

Words (or Entries) endpoints: British English (en-gb), American English (en-us), Spanish (es), Gujarati (gu), Romanian (ro).

Translations endpoints: English (en) ⇆ German (de), Russian (ru); English (en) → Spanish (es), Italian (it), Portuguese (pt).
Example calls to the Oxford Dictionaries API

To list the available registers in British English you can call the registers utility endpoint:

GET https://od-api.oxforddictionaries.com/api/v2/registers/en-gbCopy

To understand the available registers for tank in British English, you could use the Words endpoint:

GET https://od-api.oxforddictionaries.com/api/v2/words/en-gb?q=tank&fields=registersCopy

To see the definitions of the word tank when the register is informal, you could call the Words endpoint:

GET https://od-api.oxforddictionaries.com/api/v2/words/en-gb?q=tank®isters=informalCopy
Tips If you'd only like to receive registers from the response, you can use the optional fields Query Parameter as demonstrated above. Alternatively, you can filter the results of an endpoint using the registers parameter, as demonstrated above.

Regional differences

Retrieve region metadata that indicates where a word or a specific word sense is used or originates from (e.g. American English, British English, Australian). The regions feature tells you whether a particular word or sense is associated with a specific geographical or cultural area.

It can refer to:

  • the region where a word sense is primarily used (e.g. truck → American English, lorry → British English)
  • the region where a word or sense originates from (e.g. billabong → Australian)

Regions are applied at the sense level, allowing you to distinguish between region-specific meanings and usages of the same word.

Available via:

  • the Words (or Entries) endpoint
  • the Translations endpoint

Used for:

  • regional vocabulary guidance
  • dialect-aware search and filtering
  • distinguishing region-specific meanings
Element name(s) regions
Languages / dialects available

Words (or Entries) Endpoint: British English (en-gb), American English (en-us), Spanish (es), Tamil (ta).

Translations: English (en) → Chinese (zh), Spanish (es), Arabic (ar), German (de), Italian (it), Portuguese (pt), Russian (ru), Tatar (tt), Tajik (tg), Georgian (ka); Telugu (te) → English (en).
Example calls to the Oxford Dictionaries API

GET https://od-api.oxforddictionaries.com/api/v2/words/en-gb?q=dart&fields=regionsCopy – tells you that there is a specific meaning of the word dart in Australia and Canada. By simply calling the endpoint with no query parameters, you can see that dart is synonymous with the sense for cigarette in Australian and Canadian.
Tips If you'd only like to receive regions from the response, you can use the optional fields Query Parameter as demonstrated above.

Alternative spellings

Discover recognised variant spellings of a headword (e.g. color ↔ colour, dovecote ↔ dovecot). The OD API allows you to retrieve spelling variations of a word that represent:

  • regional variants (e.g. color → American English, colour → British English)
  • historical or orthographic variants (e.g. dovecot as a variant of dovecote)

Variant spellings help normalise user input, expand lookup coverage and link equivalent forms of the same lexical item.

Available via:

  • the Words (or Entries) endpoint
  • the Translations endpoint

Used for:

  • improved search recall
  • cross-regional language support
  • input standardisation
Element name(s) variantForms
Languages / dialects available

Words (or Entries) endpoint: British English (en-gb), American English (en-us), Chinese (zh).

Translations: Chinese (zh), Malay (ms) → English (en).
Example calls to the Oxford Dictionaries API

To get an alternative spelling for a word (e.g. dovecot as a variant of dovecote), you could use:

GET https://od-api.oxforddictionaries.com/api/v2/words/en-gb?q=dovecote&fields=variantFormsCopy

To get a variant spelling of a word due to regional differences (e.g. color as a US variant of British colour), you could use:

GET https://od-api.oxforddictionaries.com/api/v2/entries/en-us/color?fields=variantFormsCopy
Tips If you'd only like to receive variant form information from the response, you can use the optional fields Query Parameter as demonstrated above.

Typical Use Cases

The Lexical Data API is commonly used for:

  • Natural language processing (NLP) applications – feature extraction, morphological analysis, and token normalisation
  • Search relevance and query expansion – query expansion, ranking signals, and domain-aware retrieval
  • Language learning and assessment – grammatical features, alternative spellings, regional differences, registers and usage labels
  • Text analysis and linguistic research – etymology, inflection patterns and linguistic variation

Languages supported by the Lexical Data API capability

The Oxford Dictionaries API supports dictionary content for multiple languages. The most commonly used language for lexical data applications is English. See the full list of supported languages on the Languages page.

FAQs

What is the Lexical Data API?

The Lexical Data API is a capability of the Oxford Dictionaries API that provides structured word-level linguistic metadata such as:

  • inflections
  • etymology
  • grammatical features
  • domains
  • registers
  • regional differences
  • alternative spellings

It is designed for applications that need machine-readable information about word structure and usage, rather than or in addition to dictionary definitions or translations.

Which lexical features are available?

The Lexical Data API supports the following features:

  • inflections
  • etymology
  • grammatical features
  • domains
  • registers
  • regional differences
  • alternative spellings

Feature availability varies by language dataset. Refer to the languages/dialects row for each feature above.

Which endpoint should I use to retrieve lexical data?

For monolingual use cases use the Words (or Entries) endpoint. For bilingual use cases use the Translations endpoint.

Can I retrieve both lexical metadata and dictionary definitions in one call?

Yes.

The Words (or Entries) endpoint returns both:

  • structured lexical metadata
  • dictionary content

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