Tentacle \Ten"ta*cle\, n. [NL. tentaculum, from L. tentare to handle, feel: cf. F. tentacule. See Tempt.]

(Zo["o]l.) A more or less elongated process or organ, simple or branched, proceeding from the head or cephalic region of invertebrate animals, being either an organ of sense, prehension, or motion.

Tentacle sheath (Zo["o]l.), a sheathlike structure around the base of the tentacles of many mollusks.

Source: Webster's Revised Unabridged Dictionary (1913)