A battle cry or war cry is a yell or chant taken up in battle, usually by members of the same combatant group. Battle cries are not necessarily articulate, although they often aim to invoke patriotic or religious sentiment. Their purpose is a combination of arousing aggression and esprit de corps on one's own side and causing intimidation on the hostile side. Battle cries are a universal form of display behaviour aiming at competitive advantage, ideally by overstating one's own aggressive potential to a point where the enemy prefers to avoid confrontation altogether and opts to flee. In order to overstate one's potential for aggression, battle cries need to be as loud as possible, and have historically often been amplified by acoustic devices such as horns, drums, conches, carnyxes, bagpipes, bugles, etc..

Martial music or military music is a specific genre of music intended for use in military settings performed by professional soldiers called field musicians. Much of the military music has been composed to announce military events as with bugle calls and fanfares, or accompany marching formations with drum cadences, or mark special occasions as by military bands. However, music has been employed in battle for centuries, sometimes to intimidate the enemy and other times to encourage combatants, or to assist in organization and timing of actions in warfare. Depending on the culture, a variety of percussion and musical instruments have been used, such as drums, fifes, bugles, trumpets or other horns, bagpipes, triangles, cymbals, as well as larger military bands or full orchestras. Although some martial music has been composed in written form, other music has been developed or taught by ear, such as bugle calls or drum cadences, relying on group memory to coordinate the sounds.