The Collaborative International Dictionary of English v.0.48:

Pushpin \Push"pin`\, n.
   A child's game played with pins. --L. Estrange.
   [1913 Webster]

WordNet (r) 3.0 (2006):

pushpin
    n 1: a tack for attaching papers to a bulletin board or drawing
         board [syn: thumbtack, drawing pin, pushpin]