Entry 3 senses Webster, 1913

Drum major

/(mā"jẽr)/ · Drum· ma·jor · IPA

01 The chief or first drummer of a regiment; an instructor of drummers.

1.
The chief or first drummer of a regiment; an instructor of drummers.
2.
The marching leader of a military band.[U.S.]
3.
A noisy gathering. [R.] See under Drum, n., 4.[R.] See: Drum