# Etymonline API

> Etymonline returns English word origins and etymologies, available as a workflow and API.

Etymonline, also called Online Etymology Dictionary, provides word origin entries by part of speech; it needs an English word as input.

- Page: https://fous.com/workflows/etymonline
- Handle: `@etymonline`
- Category: [Education](https://fous.com/workflows/category/education)
- Source website: https://etymonline.com
- Last verified: Sep 29, 2026
- Fous is not affiliated with Etymonline.

## Methods

### Get word origin

Operation `get_word_origin`, version 1. 1 credit per call.

Get the origin of an English word, with separate entries by part of speech, the first date mentioned, and linked related words. Dates may be absent for some entries.

**Input**

| Field | Type | Required | Example | Description |
|---|---|---|---|---|
| `word` | string | yes | `"serendipity"` | English word to look up, such as salary. |

**Input schema**

```json
{
  "type": "object",
  "required": [
    "word"
  ],
  "properties": {
    "word": {
      "type": "string",
      "description": "English word to look up, such as salary.",
      "examples": [
        "serendipity",
        "salary"
      ]
    }
  },
  "additionalProperties": false,
  "examples": [
    {
      "word": "serendipity"
    },
    {
      "word": "salary"
    }
  ]
}
```

**Output**

| Field | Type | Example | Description |
|---|---|---|---|
| `entries` | array |  | Origin entries for the requested word, one per listed part of speech. |
| `entries[].heading` | string | `"serendipity (n.)"` | Entry heading as printed on the page. |
| `entries[].entry_link` | string | `"https://www.etymonline.com/word/serendipity"` | Link to this entry on Etymonline. |
| `entries[].earliest_date` | string or null | `"before 20c."` | First date mentioned in the origin explanation, as printed. |
| `entries[].related_entries` | array |  | Words cross-referenced from this origin explanation. |
| `entries[].origin_explanation` | string | `"\"to pay a regular salary to,\" late 15c. (Caxton), from salary (n.). Related: Salaried \"in receipt of a fixed salary\` | Full origin explanation in plain text. |

**Example input**

```json
{
  "word": "serendipity"
}
```

**Example output**

```json
{
  "entries": [
    {
      "heading": "serendipity (n.)",
      "entry_link": "https://www.etymonline.com/word/serendipity",
      "earliest_date": "before 20c.",
      "related_entries": [
        "Sri Lanka"
      ],
      "origin_explanation": "\"faculty of making happy and unexpected discoveries,\" a rare word before 20c., coined by Horace Walpole in a letter to Horace Mann that is dated Jan. 28, 1754, but which apparently was not published u…"
    }
  ]
}
```

## Quick start

Call the API with a Fous API key (`FOUS_API_KEY`). To create one, turn on Developer mode in Fous Studio, then open Keys & connections → API keys (https://app.fous.com/keys).

```bash
# First set your key: export FOUS_API_KEY='YOUR_FOUS_API_KEY'
: "${FOUS_API_KEY:?Set FOUS_API_KEY before running this example}"

curl 'https://api.fous.com/v1/query' \
  --fail-with-body --silent --show-error --max-time 120 \
  -H "Authorization: Bearer $FOUS_API_KEY" \
  -H 'Content-Type: application/json' \
  --data-raw '{
  "api": "@etymonline",
  "visibility": "public",
  "operation": "get_word_origin",
  "version": 1,
  "input": {
    "word": "serendipity"
  },
  "response": {
    "format": "json"
  }
}'
```

```python
# Save as fous.py and run with python3 fous.py. No packages needed.
# First set your key: export FOUS_API_KEY='YOUR_FOUS_API_KEY'
import json
import os
import urllib.error
import urllib.request

api_key = os.environ.get("FOUS_API_KEY")
if not api_key:
    raise RuntimeError("Set FOUS_API_KEY before running this example")

body = json.loads("{\n  \"api\": \"@etymonline\",\n  \"visibility\": \"public\",\n  \"operation\": \"get_word_origin\",\n  \"version\": 1,\n  \"input\": {\n    \"word\": \"serendipity\"\n  },\n  \"response\": {\n    \"format\": \"json\"\n  }\n}")
request = urllib.request.Request(
    "https://api.fous.com/v1/query",
    data=json.dumps(body).encode("utf-8"),
    headers={
        "Authorization": f"Bearer {api_key}",
        "Content-Type": "application/json",
    },
    method="POST",
)
try:
    with urllib.request.urlopen(request, timeout=120) as response:
        result = json.load(response)
except urllib.error.HTTPError as error:
    raise RuntimeError(f"HTTP {error.code}: {error.read().decode('utf-8', errors='replace')}") from error
if result.get("success") is False:
    raise RuntimeError(result.get("error", {}).get("message", "Request failed"))
print(json.dumps(result["data"]["output"], indent=2))
```

```typescript
// Save as fous.mts and run with npx tsx fous.mts.
// First set your key: export FOUS_API_KEY='YOUR_FOUS_API_KEY'
const apiKey = process.env.FOUS_API_KEY;
if (!apiKey) throw new Error("Set FOUS_API_KEY before running this example");

const response = await fetch("https://api.fous.com/v1/query", {
  method: "POST",
  headers: {
    "Authorization": `Bearer ${apiKey}`,
    "Content-Type": "application/json",
  },
  signal: AbortSignal.timeout(120_000),
  body: JSON.stringify({
  "api": "@etymonline",
  "visibility": "public",
  "operation": "get_word_origin",
  "version": 1,
  "input": {
    "word": "serendipity"
  },
  "response": {
    "format": "json"
  }
}),
});
type ApiResult = { success: boolean; data?: { output: unknown }; error?: { message: string } };
const result: ApiResult = await response.json();
if (!response.ok || result.success === false) {
  throw new Error(result.error?.message ?? `HTTP ${response.status}`);
}
if (!result.data) throw new Error("Missing API response data");
console.log(result.data.output);
```

Or describe the data in plain language: send `{"api":"@etymonline","prompt":"Describe the data you need, with every detail"}` to the same URL. Fous fills in the input, runs the method that fits and returns only the fields you asked for; `data.route.calls[].request` is the exact call it made. Routing is free; the run costs the same.

## Use cases

- Trace the origins of English words
- Review the first date mentioned for a word
- Explore related words cross-referenced in an origin entry

## FAQ

### Is Fous affiliated with Etymonline?

No. Fous is not affiliated with Etymonline. This workflow reads the public etymonline.com website and returns its data.

### How much does it cost?

Each run costs 1 credit. With pay-as-you-go, a credit costs 1¢; monthly plans cost less per credit.

### Do I need a Etymonline account?

No. You only need a Fous account.

### How current is the data?

Fous gets the data from etymonline.com when you run it; repeating the same request within a day may return the saved result. Fous checks this workflow automatically; it last passed a check on Sep 29, 2026.

### Where does an English word come from?

Use Get word origin with an English word to retrieve its origin explanation.

### When is a word first mentioned?

Get word origin returns the first date mentioned in each origin entry, when available.

### Which words are related to an origin entry?

Get word origin returns words cross-referenced in the origin explanation.

## Related

- [Dictionary.com API](https://fous.com/workflows/dictionary-com.md): Dictionary.com provides definitions, pronunciations, audio, examples, and word origins, plus ranked synonyms and antonyms for public Thesaurus.com entries; some word details may be unavailable.
- [Merriam-Webster API](https://fous.com/workflows/merriam-webster.md): Merriam-Webster provides definitions, pronunciations, examples, word histories, synonyms, antonyms, and related words for publicly listed entries, plus Word of the Day entries for today or published archive dates.
- [Wiktionary API](https://fous.com/workflows/wiktionary.md): A free, multilingual dictionary with word meanings and language information.
- [Cambridge Dictionary API](https://fous.com/workflows/cambridge-dictionary.md): Cambridge Dictionary provides English definitions, examples, grammar labels, and available UK and US pronunciations, plus translations and paired examples for supported languages, reflecting details shown on its pages.
- [Urban Dictionary API](https://fous.com/workflows/urban-dictionary.md): Urban Dictionary provides crowdsourced slang definitions and examples, plus up to 30 newest Words of the Day with featured dates.
- [Investopedia API](https://fous.com/workflows/investopedia.md): Financial education, investing explanations, and a finance dictionary.
- [WordReference API](https://fous.com/workflows/wordreference.md): Dictionary translations and language reference.
- [RhymeZone API](https://fous.com/workflows/rhymezone.md): RhymeZone finds rhymes, similar-sounding words, and related words, including synonyms, opposites, descriptions, and associations; some results lack relevance scores or syllable and part-of-speech details.
- [All Education workflows](https://fous.com/workflows/category/education)