# OpenVerbs Dictionary – Word Definition Lookup

> OpenVerbs Dictionary – Word Definition Lookup is a paid API for AI agents from dictionary.openverbs.com, paid per call via x402, $0.002/call, status unknown (last checked 2026-09-13).

Returns definitions, part of speech, example sentences, and synonyms for an English word, with optional filtering by part of speech.

## Facts

- Endpoint: POST https://dictionary.openverbs.com/v1/define
- Price: $0.002/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-13
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/openverbs-dictionary-word-definition-lookup-81a2fc59
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_XwK0KJbrH1nguagSSc9EF

Status and success rate cover calls made through Zero and Zero's own probes. Third-party monitors may report differently.

## How to call it through Zero

Zero handles the 402 payment challenge and records the run. With the Zero CLI installed (`npm i -g @zeroxyz/cli`):

```sh
zero fetch --capability openverbs-dictionary-word-definition-lookup-81a2fc59 -d '<json body>'
```

Example prompt: What does the word 'ephemeral' mean? Give me its definitions, example sentences, and synonyms — specifically the adjective sense.

## When to prefer this

Choose this endpoint when you need structured, sense-by-sense English word definitions with example sentences and synonyms in a single call. Prefer it over general web search when you need clean, machine-readable lexical data — especially when you want to filter by part of speech. It complements the sibling synonyms and antonyms endpoints on the same provider for richer vocabulary lookups.

## Known failure modes

- Unknown or misspelled word returns found:false with HTTP 200 (not an error)
- Empty or blank word field rejected with validation error
- Invalid part-of-speech filter value (not in enum) causes request failure
- Network or payment errors may prevent the call from completing
- Very rare or highly technical words may return found:false even if valid

## How this service works

Look up the definitions of an English word. Returns one entry per sense with its part of speech, definition, example sentences and synonyms. Optionally filter by part of speech. An unknown word returns found:false with a 200.

## Output

Returns an array of sense entries for the word, each containing its part of speech, definition text, example sentences, and synonyms. If the word is not found in the dictionary, returns a found:false flag with HTTP 200 rather than an error.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "required": [
  "input"
 ],
 "properties": {
  "input": {
   "type": "object",
   "required": [
    "type",
    "method",
    "bodyType",
    "body"
   ],
   "properties": {
    "body": {
     "type": "object",
     "required": [
      "word"
     ],
     "properties": {
      "pos": {
       "enum": [
        "noun",
        "verb",
        "adjective",
        "adverb"
       ],
       "type": "string",
       "description": "Optional part-of-speech filter."
      },
      "word": {
       "type": "string",
       "minLength": 1,
       "description": "The word to look up."
      }
     },
     "additionalProperties": false
    },
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "POST"
     ],
     "type": "string"
    },
    "bodyType": {
     "enum": [
      "json",
      "form-data",
      "text"
     ],
     "type": "string"
    }
   },
   "additionalProperties": false
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/openverbs-dictionary-word-definition-lookup-81a2fc59/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from dictionary.openverbs.com](https://www.zero.xyz/host/dictionary.openverbs.com/llms.txt)