lancetfish \lan"cet*fish`\, lancet fish \lan"cet fish`\n. (Zool.) A large, elongated, scaleless, voracious, deep-sea fish ({Alepidosaurus ferox}), having long, sharp, lancetlike teeth and a long saillike dorsal fin. [WordNet sense 1] Syn: lancet fish, wolffish. [1913 Webster + WordNet 1.5] 2. The doctor, or surgeon fish. [1913 Webster]