/truy suy"klik, -sik"lik/ , adj.
1. pertaining to or embodying three cycles.
n.
2. Also called tricyclic antidepressant . Pharm. any of a group of pharmacologically active substances, as imipramine, that share a common three-ring structure, used to treat depression and cocaine abuse.
[ 1890-95; TRI- + CYCLIC ]