'friendly fire' definitions:

Definition of 'friendly fire'

From: WordNet
noun
Fire that injures or kills an ally [syn: friendly fire, fratricide]

Definition of 'friendly fire'

From: GCIDE
  • friendly fire \friend"ly fire`\, n. (Mil.) Weapons fire[9], such as artillery or aerial bombardment, from one's own forces; -- used mostly when troops do damage or cause casualties among their own forces; as, the tank was hit by friendly fire. [PJC]