n A broad piece of defensive armor, carried on the arm, formerly in general use in war, for the protection of the body.
n (botany) In lichens, a hardened cup or disk surrounded by a rim and containing the fructification, or asci.
n (mining) A framework used to protect workmen in making an adit under ground, and capable of being pushed along as excavation progresses.
n (transport) A sign or symbol, usually containing numbers and sometimes letters, identifying a highway route.