in the military system of the ancients, an instrument of the nature of a trumpet, upon the sounding of which the ensigns were to march without the soldiers; whereas, when the trumpet sounded, the soldiers were to move forward without the ensigns. The cornets and bugles sounded the charge and retreat, and the cornets and trumpets sounded during the course of the battle.

in modern military economy, denotes an officer in the cavalry who bears the standard or colours of a troop or squadron.

The cornet is the third commissioned officer in the company, and commands in the absence of the captain and lieutenant. He takes his title from his ensign, which is square; and he is supposed to be called by the name of cornet, from cornu, because placed on the wings, which form the points or horns of the army. Others derive the name from cornet, alleging that it was the ancient custom for these officers to wear coronets or garlands on their heads.