cheval de bataille

[shuh-val duh ba-tah-yuh]
noun, plural che·vaux de ba·taille [shuh-vohduh ba-tah-yuh] /ʃə voʊdə baˈtɑ yə/. French.
  1. a horse used in battle; charger.
  2. a favorite topic of discussion, argument, etc.
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018