1. (n.) A powerful brass instrument of the trumpet kind, thought by some to be the ancient sackbut, consisting of a tube in three parts, bent twice upon itself and ending in a bell. The middle part, bent double, slips into the outer parts, as in a telescope, so that by change of the vibrating length any tone within the compass of the instrument (which may be bass or tenor or alto or even, in rare instances, soprano) is commanded. It is the only member of the family of wind instruments whose scale, both diatonic and chromatic, is complete without the aid of keys or pistons, and which can slide from note to note as smoothly as the human voice or a violin. Softly blown, it has a rich and mellow sound, which becomes harsh and blatant when the tones are forced; used with discretion, its effect is often solemn and majestic.

2. (n.) The common European bittern.

English horn alpenhorn alphorn althorn alto horn ballad horn baritone bass horn bassoon block flute bombard bourdon brass choir brass wind brass-wind instrument brasses bugle bugle horn cello claribel clarinet clarion concert flute cornet cornet-a-pistons corno di caccia cornopean cromorna cymbel diapason double-bell euphonium dulciana euphonium flute stop foundation stop fourniture gamba gedeckt gemshorn harmonic flute helicon horn hunting horn hybrid stop key trumpet koppel flute larigot lituus lur mellophone melodia mixture mutation stop nazard oboe octave ophicleide orchestral horn organ stop piccolo plein jeu pocket trumpet posaune post horn principal quint quintaten rank ranket reed stop register rohr flute sackbut saxhorn saxtuba serpent sesquialtera shawm slide trombone sliphorn sousaphone spitz flute stop stopped diapason stopped flute string diapason string stop tenor tuba tierce tremolo tromba trumpet tuba twelfth unda maris valve trombone valve trumpet vibrato viola voix celeste vox angelica vox humana