thumbtack

noun

1. a tack with a large, flat head, designed to be thrust into a board or other fairly soft object or surface by the pressure of the thumb.

verb (used with object)

2. to attach or tack by means of a thumbtack.

noun

1. mainly US and Canadian a short tack with a broad smooth head for fastening papers to a drawing board, etcAlso called (esp in Britain): drawing pin

n.tack with a broad, flat head which may be driven by pressure from the thumb, 1884, from thumb (n.) + tack (n.1).