{i} projectiles shot from a weapon (bullets, grenades, bomb shells, etc.); something used to attack
You can describe information that you can use against someone in an argument or discussion as ammunition. The improved trade figures have given the government fresh ammunition
any nuclear or chemical or biological material that can be used as a weapon of mass destruction
Ammunition is bullets and rockets that are made to be fired from guns. He had only seven rounds of ammunition for the revolver
projectiles to be fired from a gun information that can be used to attack or defend a claim or argument or viewpoint; "his admission provided ammunition for his critics"