(grammar) In a clause: the word or word group (usually a noun phrase) about whom the statement is made. In active clauses with verbs denoting an action, the subject and the actor are usually the same.

A bird of the order of Struthioniformes, a diverse group of large running, flightless birds, mostly extinct, but including the cassowary, elephant bird, emu, kiwi, moa, ostrich, rhea and tinamou

(anatomy) The tapered lower end of the spinal cord.

(idiomatic) To ignore or deliberately overlook.