Definition of knife

• n. - An instrument consisting of a thin blade, usually of steel and having a sharp edge for cutting, fastened to a handle, but of many different forms and names for different uses; as, table knife, drawing knife, putty knife, pallet knife, pocketknife, penknife, chopping knife, etc..
• n. - A sword or dagger.
• v. t. - To prune with the knife.
• v. t. - To cut or stab with a knife.