What is "marching money"

Marching \March"ing\, a. & n., fr. March, v. Marching money (Mil.), the additional pay of officer or soldier when his regiment is marching. In marching order (Mil.), equipped for a march. Marching regiment. (Mil.)

1. A regiment in active service.

2. In England, a regiment liable to be ordered into other quarters, at home or abroad; a regiment of the line.