Lancet \Lan"cet\, n. [F. lancette, dim. of lance lance. See Lance.]

1. A surgical instrument of various forms, commonly sharp-pointed and two-edged, used in venesection, and in opening abscesses, etc.

2. (Metal.) An iron bar used for tapping a melting furnace. --Knight.

Lancet arch (Arch.), a pointed arch, of which the width, or span, is narrow compared with the height.

Lancet architecture, a name given to a style of architecture, in which lancet arches are common; -- peculiar to England and 13th century.

Lancet fish. (Zo["o]l.)
   (a) A large, voracious, deep-sea fish (Alepidosaurus ferox), having long, sharp, lancetlike teeth.
   (b) The doctor, or surgeon fish.

Source: Webster's Revised Unabridged Dictionary (1913)