vocabularies

The wet/dry operating mode a suction (vacuum) cleaner runs in: dry only (dust and debris), wet-and-dry (also picks up liquids), or spray-extraction (sprays a cleaning solution then extracts it, for carpets and upholstery). A token category recurring across vacuum cleaners (L11); a growing vocabulary (L13). Its members are VALUES of one VacuumCleaner kind, not separate classes — a wet-&-dry vac, a dry vac and a carpet/sofa extraction cleaner share the same slot-profile and differ only by this mode.

Answers the question: operation mode.