Head"er, (-r), n. 1. One who, or that which, heads nails, rivets, etc.,
esp. a machine for heading.
2. One who heads a movement, a party, or a mob; head; chief; leader.
[R.]
3. (Arch.) (a) A brick or stone laid with its shorter face or head in
the surface of the wall. (b) In framing, the piece of timber fitted
between two trimmers, and supported by them, and carrying the ends of
the tailpieces.