Lexicon

Works with Claude and your AI tools

Lexicon

Hear a word you don't know? Tell your AI to save it. Lexicon looks it up, puts it on your widget and brings it back until it's yours.

Start free Coming soon on theApp Store

See how it works ›

Your AI, your words

Ask your AI. It's saved.

Go about your day. When a word stops you, tell the AI you already use. Lexicon fills it in, puts it on your widget and quizzes you until it sticks.

  1. Meet a word

    In a book, a meeting, a podcast or a conversation. Anywhere you hear one you don't know.

  2. Ask your AI to save it

    One sentence to Claude or any app that speaks MCP. Lexicon adds the meaning, examples and origin.

  3. See it every day

    It shows up on your widget, then comes back in review until you know it for good.

Claude and MCP apps

Connect Lexicon once with your account's address and token. Your AI can save words and quotes, look up what you've saved and quiz you.

Obsidian and Markdown

Send your whole notebook to your Obsidian vault as Markdown, or paste a note of words in and Lexicon fills them all.

Connect your AI ›

Grow

A few new words a day. A sharper mind for life.

Save, see, review, use. The same small loop every day turns words you've met once into words you use without thinking.

The app

Every word you meet. Kept for good.

The word sonder, with its meaning, example, synonyms and origin. The word laconic after Fill, with its meaning, example, synonyms and origin. The Quotes tab with three quotes in serif type. A flashcard for sonder with the Again, Hard, Good and Easy buttons. Home Screen and Lock Screen widgets showing a word and a quote.

Learn

Meet it once. Remember it for years.

Flashcards that know when

Spaced repetition brings each word back just before you'd forget it. Miss one and it returns in ten minutes; the ones you know come back less and less often.

Fill does the looking up

Meaning, part of speech, examples and origin from a free dictionary. Add your own AI provider for the rest.

On every screen

Small, medium and large widgets for the Home Screen, and two for the Lock Screen.

Use it in a sentence

Write your own sentence and your AI tells you if it fits.

Save from anywhere

Share text from any app, add a word with Siri, or open the web app in any browser.

Organized your way

Tags, favorites and search across everything you've saved.

iPad

Room to read. Room to think.

Lexicon on iPad: the word list beside the word and quote of the day.

Private

Your words. Only yours.

Every account gets a notebook of its own. Nothing is shown to anyone else, and nothing is sold.

Ads, analytics, tracking
None
Your notebook
Private to your account
Leave anytime
Export or delete in Settings
AI
Your provider and key, only when you ask

Read the privacy policy ›

Self-hosted

Prefer your own server? Three steps.

Any computer that stays on will do. The server has no dependencies and keeps everything in one SQLite file.

  1. Install Node.js 24

    On a Mac, a Linux box, a Raspberry Pi or a small cloud server.

  2. Start it with a token

    Pick a long random token. Only someone who has it can open your notebook.

    node --env-file=.env server/index.js

  3. Connect the app

    Give the server an HTTPS address with a reverse proxy or tunnel, then enter it and your token in the app.

Full setup steps ›

Save your first word today.

Make a free account, connect your AI and start growing your vocabulary in a minute.

Start free Coming soon on theApp Store