Lexicon
A desktop knowledge dictionary for structured learning and technical note-taking — maps, terms, rich metadata, and typed links between concepts.
Why Lexicon?
Your knowledge deserves more than a flat pile of notes. Lexicon organizes what you learn into a structured, searchable, interlinked dictionary — stored locally in a single SQLite file.
Local-first storage
Everything lives in one SQLite database file on your disk. No cloud, no account, no lock-in — back it up by copying a single file.
Maps and terms
Group terms into top-level maps such as C++, Databases, or Networking, with full create/edit/delete support.
Rich metadata
Every term carries aliases, tags, flags, a status, an understanding level, and a pinned state — so you always know where you stand.
Typed relationships
Connect concepts with links and backlinks typed as Is A, Part Of, Depends On, Related, and more — building a real concept graph.
Markdown editor
Write term content in Markdown with a formatting toolbar and a live rendered preview, powered by the md4qt parser.
Fast search & filters
Search across titles, disambiguations, aliases, tags, and flags. Combine filters for map, tag, flag, status, understanding, and pinned.
Built for large datasets
Pagination controls and sortable columns keep even very large lexicons fast and easy to browse.
Global overviews
Read-only overviews of all tags, flags, and aliases with usage counts help you keep your vocabulary consistent.
Light and dark mode
Switch themes from the View menu — your preference is remembered between sessions. This website has it too, try the moon button above.
Choose your path
The documentation is split into two sections, depending on what you want to do with Lexicon.
For Users
Everything you need to install Lexicon and organize your knowledge like a pro.
- Installation and first launch
- Creating maps and terms
- The Markdown content editor
- Tags, flags, aliases, links & backlinks
- Search, filtering, backup, and troubleshooting
For Developers
Dive into the codebase, build from source, and contribute.
- Building with CMake and Qt 6
- Application architecture and source layout
- SQLite schema and the migration system
- Roadmap and TODO list
- Contributing guidelines and license
Up and running in a minute
Lexicon builds from source with CMake and Qt 6. On Debian or Ubuntu it takes three commands:
sudo apt install -y build-essential cmake qt6-base-dev libqt6sql6-sqlite
cmake -S . -B build -DCMAKE_BUILD_TYPE=Release && cmake --build build --target Lexicon -j
./build/LexiconSee it in action
The term editor gives every concept five focused tabs: General, Content, Metadata, Links, and Backlinks.
What's next
Lexicon is actively developed. Highlights from the roadmap:
📤 Export to CSV / JSON
Take your data anywhere with structured exports.
🌐 Static HTML export
Publish your lexicon as a browsable static website.
🖧 Built-in HTTP server
Serve your knowledge base to other devices on your network.