v. & n.
v. 1 tr. & intr. push with the head or horns. 2 a intr. (usu. foll. by against, upon) come with one end flat against, meet end to end with, abut. b tr. (usu. foll. by against) place (timber etc.) with the end flat against a wall etc.
n. 1 a push with the head. 2 a join of two edges. butt in interrupt, meddle.
[ ME f. AF buter, OF boter f. Gmc: infl. by BUTT(2) and ABUT ]