How to define brush?

To define brush, you need to consider its multiple parts of speech and contexts, but a comprehensive definition covers its main uses. As a noun, brush can be defined as a tool consisting of a handle with bristles, fibers, or wires attached, used for cleaning, sweeping, painting, grooming, or scrubbing, such as toothbrush, hairbrush, or paintbrush. Another noun definition is dense, low-growing woody vegetation, shrubs, small trees, and undergrowth forming thickets or scrubland, also called underbrush, scrub, or chaparral, as in brush in the forest. As a verb, to brush means to clean, sweep, or groom with a brush, to apply paint with a brush, to touch lightly in passing, or to dismiss or ignore, as in brush off. As an adjective phrase, brush can describe something related to brushwood. In other fields, brush has specialized definitions, such as in electrical motors a brush is a component that conducts current, in dance a brush is a light sweeping foot movement, in art a brushstroke. So to define brush fully, you should specify part of speech and context, but core ideas are bristly tool, shrubby vegetation, and light touching or sweeping action, all derived from Old French brosse meaning bundle of twigs.