Open Dict · Dictionary & AI

A lightweight dictionary.Your library. Your AI.

A small app for the dictionaries you choose. Import open, free and open-source dictionaries, look up offline, and bring your own AI with your own prompts. No subscription.

iPhone / iPad · Coming soon

Explore all features

One purchase. Mac, iPad, iPhone.Mac · iPad · iPhone

Open Dict · Mac · Original layouts, light or dark

Open Dict · iPhone · Keep the sentence that matters

Open dictionary formats

MDX / MDD

MDX / MDD

An established dictionary format with rich layouts. MDX stores entries; companion MDD files can hold images and audio. A broad community library ecosystem.

MOBI

MOBI

A dictionary format used in the Kindle ecosystem. Reuse your MOBI dictionaries or explore free dictionaries built from Wiktionary.

StarDict

StarDict

A mature, open dictionary format with broad cross-platform support. FreeDict and WikDict offer many free, open multilingual dictionaries.

dictd

dictd

An established open format from the DICT ecosystem, focused on indexed text entries. FreeDict offers free multilingual dictionaries.

TXT / TSV

TXT / TSV

Lightweight plain-text and tab-separated formats. Easy to edit your own glossary or import open vocabulary data, with simpler layouts than rich-text dictionaries.

Features

A closer look at every word.

Read original dictionary entries, compare sources, ask for a different explanation, and save what you want to remember.

Small app, focused experience

The Mac app is about 5.2 MB. No app account, bundled online services or service subscription. Just a place for words and reading.

Open formats, your own library

Import quality open, free, open-source and personal dictionaries in MDX/MDD, MOBI, StarDict, dictd, TXT and TSV.

Your model, your explanation

Choose a provider and a specific model. Shape the prompt for concise meanings, usage comparisons or multilingual examples.

MDX · MOBI · StarDict · dictd

One search, multiple dictionaries

Search prefixes, contained text or phrases across your library. Switch dictionaries to compare definitions and examples.

Explore the features →

DeepSeek · Kimi · GLM · Claude · Gemini

AI definitions, your way

Use your own API key and choose a model. Start with built-in prompts or create concise definitions, learner explanations and multilingual examples.

Why bring your own API key? →

Universal App · Mac / iPad / iPhone

One purchase. Mac, iPad, iPhone.

Permanently unlock unlimited dictionaries with one purchase. Your purchase works on Mac, iPad and iPhone with the same Apple Account. No subscription.

Start free: Use up to 5 dictionaries with no other feature restrictions, free for as long as you like.
Unlock unlimited dictionaries: Mac · iPad · iPhone

iPhone / iPad · Coming soon

Open Dict · iPad · Look up here, review anywhere — **iCloud**History, word groups, notes and AI configuration stay with you through your personal iCloud account.

FAQ

Get started

Answers about dictionaries, AI, purchases and your devices.

All questions →Help →

What can I use for free?

The free version supports up to 5 dictionaries, with no other feature restrictions or time limit. A one-time purchase removes the dictionary limit permanently. Open Dict has no subscription.

Do I need my own dictionaries? Where can I find them?

Yes. Import the dictionaries you want and build your own library. These are useful starting points: FreeMdict hosts MDX community discussions and resources; FreeDict, WikDict and Wiktionary Dictionaries offer free dictionaries built from open data. Download a supported format and import it into Open Dict.

FreeMdict ↗MDX / MDD
FreeDict ↗StarDict · dictd
WikDict ↗StarDict
Wiktionary Dictionaries · GitHub ↗MOBI · StarDict · TSV

These resources are maintained by third-party communities or websites and may change at any time. Open Dict cannot ensure their availability.

Can I look up words offline?

Yes. Imported local dictionaries work offline. AI explanations connect to your chosen provider, and iCloud sync needs an internet connection.