n. any of several wild plants, esp.: 1 (in full pellitory of Spain) a composite plant, Anacyclus pyrethrum, with a pungent-flavoured root, used as a local irritant etc. 2 (in full pellitory of the wall) a low bushy plant, Parietaria judaica, with greenish flowers growing on or at the foot of walls.
[ (sense 1) alt. f. ME f. OF peletre, peretre f. L pyrethrum f. Gk purethron feverfew: (sense 2) ult. f. OF paritaire f. LL parietaria f. L paries -etis wall ]