Many of the vocabulary words on ajvocab.com are classified as geography, music, slang, author, etc. thus making it possible to check how many, i.e. [avian] words are in our James Joyce Ulysses vocabulary collection, or how many [obsolete] words are used in Hamlet.

Many of these categories have category-specific icons, such as openstreetmap.org and wikivoyage.org for the [geography] words.