*bhau-

mid-13c., "to end at, to border on, touch at the end," from Old French aboter, abuter "join end to end, touch with an end" (13c.), and abouter "join end to end," from à "to" (see ad-) + boter, bouter "to strike, push," from a Germanic source (ultimately from PIE root *bhau- "to strike"). Compare butt (v.). Related: Abutted; abutting.

"beat with a stick, thrash," 1530s, perhaps from the cookery sense of baste (v.2) or from Old Norse beysta "to beat" or a similar Scandinavian source (such as Swedish basa "to beat, flog," bösta "to thump"), from Proto-Germanic *baut-sti-, from PIE root *bhau- "to strike."