A base, upon which an ornament may or may not be positioned, placed on the three angles of a pediment. The ornament may also be called an acroterion.
Acroterion (pl. acroteria) - plinths for statues, etc, at the apex and ends of a pediment. Can also refer to the statues themselves.
a sculptural element on a base, placed atop a pediment at its apex or ends