noun: (chemistry) Initialism of uridine diphosphate.
noun: (computing) Initialism of User Datagram Protocol (jocular: "Unreliable Datagram Protocol," pertaining to the lossy protocol's inherent bias to drop packets under heavy load.)
noun: (Usenet) Initialism of Usenet Death Penalty.
noun: (Ireland, politics) Initialism of Ulster Democratic Party.
noun: (military, US) Initialism of Unit Deployment Program.
