(bridge) a playing card with a value sufficiently high to insure taking a trick in a particular suit; "if my partner has a spade stopper I can bid no trump"
close or secure with or as if with a stopper; "She stoppered the wine bottle"; "The mothers stoppered their babies' mouths with pacifiers"
(biology) the field of science concerned with processes of communication and control (especially the comparison of these processes in biological and artificial systems)