But"tress (?), n. [OE. butrasse, boterace, fr. F. bouter to push; cf. OF. bouteret (nom. sing. and acc. pl. bouterez) buttress. See Butt an end, and cf. Butteris.]
1. Arch.
A projecting mass of masonry, used for resisting the thrust of an arch, or for ornament and symmetry.
⇒ When an external projection is used merely to stiffen a wall, it is a pier.
2.
Anything which supports or strengthens.
"The ground pillar and
buttress of the good old cause of nonconformity."
South.
Flying buttress. See Flying buttress.
© Webster 1913.
But"tress (?), v. t. [imp. & p. p. Buttressed (); p. pr. & vb. n. Buttressing.]
To support with a buttress; to prop; to brace firmly.
To set it upright again, and to prop and buttress it up for duration.
Burke.
© Webster 1913.