A bugle call is a short tune, originating as a military signal announcing scheduled and certain non-scheduled events on a military installation, battlefield, or ship.
Historically bugle calls indicated the change in daily routines of camp. Each morning a bugler would sound "Assembly of Buglers." At this signal, all the buglers would come together at their commander's tent. Soon, "Assembly" commanded the soldiers to form ranks and stand at attention for roll call. Every duty around camp had its own bugle call, and since cavalry had horses to look after, they heard twice as many signals as regular infantry. "Boots and Saddles" was the most imperative of these signals and had an electrifying effect on camp. It was sounded without warning at any time of day or night, and sent the men flying to equip themselves and their mounts. In addition, buglers relayed instructions from officers to soldiers during battle. Bugle calls translated commanders' orders into action on the front lines. Bugle signals could instruct the company to go Forward, To the Left, To the Right, About, Rally on the Chief, Trot, Gallop, Commence Firing, Disperse, March, and Cease Fire.