Pronunciation: (bu'tris),[key] —n. 1. any external prop or support built to steady a structure by opposing its outward thrusts, esp. a projecting support built into or against the outside of a masonry wall.
2. any prop or support.
3. a thing shaped like a buttress, as a tree trunk with a widening base.
4. a bony or horny protuberance, esp. on a horse's hoof.
—v.t. 1. to support by a buttress; prop up.
2. to give encouragement or support to (a person, plan, etc.).