(1):

(n.) A shell, used as a die. See Props.

(2):

(v. t.) To support, or prevent from falling, by placing something under or against; as, to prop up a fence or an old building; (Fig.) to sustain; to maintain; as, to prop a declining state.

(3):

(v.) That which sustains an incumbent weight; that on which anything rests or leans for support; a support; a stay; as, a prop for a building.