'rallying cry' definitions:

Definition of 'rallying cry'

(from WordNet)
noun
A slogan used to rally support for a cause; "a cry to arms"; "our watchword will be `democracy'" [syn: war cry, rallying cry, battle cry, cry, watchword]
noun
A yell intended to rally a group of soldiers in battle [syn: war cry, war whoop, rallying cry, battle cry]

Synonyms of 'rallying cry'

From: Moby Thesaurus