v. t. & i. [ imp. & p. p. Trepanned p. pr. & vb. n. Trepanning. ] [ Cf. F. trépaner. See Trepan a saw. ] (Surg.) To perforate (the skull) with a trepan, so as to remove a portion of the bone, and thus relieve the brain from pressure or irritation; to perform an operation with the trepan. [ 1913 Webster ]

n. [ See Trapan. ] 1. A snare; a trapan. [ 1913 Webster ]

Snares and trepans that common life lays in its way. South. [ 1913 Webster ]

2. a deceiver; a cheat. [ 1913 Webster ]

He had been from the beginning a spy and a trepan. Macaulay. [ 1913 Webster ]

v. t. To insnare; to trap; to trapan. [ 1913 Webster ]

Guards even of a dozen men were silently trepanned from their stations. De Quincey. [ 1913 Webster ]

n. [ F. trépan (cf. Sp. trépano, It. trepano, trapano), LL. trepanum, fr. Gr. &unr_; a borer, auger, trepan, fr. &unr_; to bore, &unr_; a hole. Cf. Trephine. ] 1. (Surg.) A crown-saw or cylindrical saw for perforating the skull, turned, when used, like a bit or gimlet. See Trephine. [ 1913 Webster ]

2. (Mining) A kind of broad chisel for sinking shafts. [ 1913 Webster ]

n. [ Malay trīpang. ] (Zool.) Any one of several species of large holothurians, some of which are dried and extensively used as food in China; -- called also bêche de mer, sea cucumber, and sea slug. [ Written also tripang. ] [ 1913 Webster ]

☞ The edible trepangs are mostly large species of Holothuria, especially Holothuria edulis. They are taken in vast quantities in the East Indies, where they are dried and smoked, and then shipped to China. They are used as an ingredient in certain kinds of soup. [ 1913 Webster ]

v. t. To trepan. [ Obs. ] “By trepanizing the skull.” Jer. Taylor. [ 1913 Webster ]

n. One who trepans. “ Pitiful trepanners and impostors.” Gauden. [ 1913 Webster ]