ETYM French bistouri.
A surgical instrument consisting of a slender knife, either straight or curved, generally used by introducing it beneath the part to be divided, and cutting towards the surface.
Narrow surgical knife; small, narrow surgical knife.

ETYM French lancette, dim. of lance lance. Related to Lance.
Pointed surgical instrument; pointed window or arch.
A surgical knife with a pointed double-edged blade; used for punctures and small incisions; SYN. lance.

ETYM Latin scalpellum, dim. of scalprum a knife, akin to scalpere to cut, carve, scrape: cf. French scalpel.
A thin straight surgical knife used in dissection and surgery.