Categories that fit together.

Browse the public vocabulary built with OntoDAG, where anything can sit under several categories at once. Create an account to file your own things under it, and share them by filing them under people. New here? The guide walks you through it.

Vocabularies

core 4,614 categories
An upper ontology of everyday things in ten branches — objects, agents, places, events, information — built by consensus over WordNet, SUMO, OpenCyc, schema.org, Wikidata and others.
physics 195 categories
Forces, fields, particles and the quantities that measure them.
mathematics 614 categories
Structures, numbers, functions and the branches that study them.
chemistry 241 categories
Elements, compounds, reactions and laboratory practice.
biology 344 categories
Organisms, cells, anatomy and the processes of life.
medicine 1,035 categories
Diseases, symptoms, treatments, drugs and clinical practice.
ai 675 categories
Models, learning methods, agents and the vocabulary of machine intelligence.
economics 1,125 categories
Markets, money, assets, firms and financial instruments.
computing 1,356 categories
Hardware, software, networks, languages and data.
geography 993 categories
Continents, countries, landforms and bodies of water.
space 351 categories
Stars, planets, spacecraft and the rest of the sky.

Dimensions and units

prelude 19 categories
The everyday dimensions: time, weight, length and the like — categories that carry typed, ordered values.
crypto-core 12 declarations
Units for BTC, ETH, BZZ and DAI, with their protocol denominations.
crypto-majors 31 declarations
Units for the market's major coins.
stablecoins 7 declarations
Units for the common stablecoins.
fiat-iso4217 154 declarations
Units for about 150 national currencies (ISO 4217).