A horn used by hunters.

A copper instrument of the horn quality of tone, shorter and more conical that the trumpet, sometimes keyed; formerly much used in military bands, very rarely in the orchestra; now superseded by the cornet; -- called also the Kent bugle.

a brass instrument without valves; used for military calls and fanfares

a brass musical instrument

Brass instrument that evolved from the earlier military, or field, trumpet.

A musical instrument, when made in glass with a single loop, may be functional. MILLER p.297

The bugle is one of the simplest brass instruments; it is essentially a small natural horn with no valves. All pitch control is done by varying the player's embouchure, since the bugle has no other mechanism for controlling pitch. Consequently, the bugle is limited to notes within the harmonic series.