knife (a tool with a blade and a handle, used for cutting or as a weapon): We eat with fork and knife. He was carrying a knife.
cleaver (a heavy tool having a large square blade for cutting up large pieces of meat): Use the cleaver to cut the meat.
blade (the edge of a knife, axe, or saw, which is used for cutting): The axe blade was sharp. (blade also means cutting tool: The blade cut deep into the wood.)
dagger (a short-pointed knife which is sharp on both sides, used as a weapon): Put the dagger in its sheath.
scalpel (a small sharp knife, used by doctors during operations): We need surgical instruments like scissors, scalpels and tweezers.
machete (a large knife with a wide heavy blade, used for cutting trees and plants or as a weapon): He used his machete to clear a path through the jungle.
penknife (a small knife with one blade or more blades which folds inside its handle): I don’t have any weapon, not even a penknife.
switchblade (a pocketknife with a blade inside its handle which springs out when a button is pressed): They found a switchblade on the ground.
