Source : Webster's Revised Unabridged Dictionary (1913)

Rostrum \Ros"trum\ (-tr[u^]m), n.; pl. L. {Rostra}, E.
   {Rostrums}. [L., beak, ship's beak, fr. rodere, rosum, to
   gnaw. See {Rodent}.]
   1. The beak or head of a ship.