Battle cry

A battle cry is a yell or chant taken up in battle, usually by members of the same military unit. 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 (i.e., threat display) 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. (see also martial music).

Battle cries are closely related to other behavioral patterns of human aggression, such as war dances and taunting, performed during the "warming up" phase preceding the escalation of physical violence. From the Middle Ages, many cries appeared on standards and were adopted as mottoes, an example being the motto "Dieu et mon droit" ("God and my right") of the English kings. It is said that this was Edward III's rallying cry during the Battle of Crécy. The word "slogan" originally derives from sluagh-gairm or sluagh-ghairm (sluagh = "people", "army", and gairm = "call", "proclamation"), the Scottish Gaelic word for "gathering-cry" and in times of war for "battle-cry". The Gaelic word was borrowed into English as slughorn, sluggorne, "slogum", and slogan.

Antiquity

 * The war cry is an aspect of epic battle in Homer: in the Iliad, Diomedes is conventionally called "Diomedes of the loud war cry." Hellenes and Akkadians alike uttered the onomatopoeic cry "alala" in battle, a cry not far from "Alleluia".
 * The troops of ancient Athens, during the Medic Wars and the Peloponnesian War were noted for going into battle shouting "Alala or Alale!", which was supposed to emulate the cry of the owl, the bird of their patron goddess Athena.
 * The Western Huns attacked with terrifying battle cries.

Middle Ages

 * Each Turkic tribe and tribal union had its distinct Tamga (seal), totemic Ongon bird, and distinct Uran (battle cry) (hence the Slavic Urah "battle cry"). While tamgas and ongons could be distinct down to individuals, the hue of horses and uran battle cries belonged to each tribe, were passed down from generation to generation, and some modern battle cries were recorded in antiquity. On split of the tribe, their unique distinction passed to a new political entity, endowing different modern states with the same  uran battle cries of the split tribes, for example Kipchak battle cry among Kazakhs, Kirgizes, Turkmens, and Uzbeks. Some larger tribes' uran battle cries:
 * Kipchak – "ay-bas" ("lunar head").
 * Kangly (Kangars) – "bai-terek" ("sacred tree").
 * Oguzes – "teke" ("mount")
 * Santiago! was a war cry of Spanish troops during the Reconquista, and of the Spanish Empire.
 * The Takbir (Allāhu Akbar (الله أكبر), "God is Great") has traditionally been used by Muslims as a battle cry.
 * On August 14, 1431, the whole Holy Roman Empire army (of the 4th anti-Hussite crusade) was defeated by the Hussites in the Battle of Domažlice. Attacking imperial units started to retreat after hearing Ktož jsú boží bojovníci ("Ye Who Are Warriors of God") choral and were annihilated shortly after.

Pre-modern

 * "Har Har Mahadev", was the battlecry used by the Marathas during their rule in Indian SubContinent.
 * The Sikh slogan or jaikara, battle cry, Bole So Nihal...Sat Sri Akal popularized by Guru Gobind Singh.
 * The rebel yell was a battle cry used by Confederate soldiers during the American Civil War.

Modern

 * During the early 1910s, mainland Greeks spontaneously employed the Aera ("Wind")!, a battle cry previously used by the Cretan Gendarmerie. It became standardized in the land Armed Forces of Greece, during the constant warfare of the next 30 years: the Balkan Wars, World War I, the Asia Minor Campaign, and World War II.
 * During World War II, banzai served as a battle cry of sorts for Japanese soldiers, particularly in a "banzai charge".
 * Oorah is a war cry used by United States Marine Corps, as well as by Russian Ground Forces.
 * Let's roll is a popular military and civilian cry in the United States since it was used when passengers rushed the hijackers of flight United 93.
 * During Operation Torch in North Africa, "Woho/Wahaw Mahommed" became the battle cry for British airborne forces, taken from the manner in which nomadic locals used to communicate over long distances by shouting from hill tops.