Adjoin at one end (4)

I believe the answer is:
abut
'adjoin at one end' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for abut that I've seen before include "Of building or land, end or lean against" , "Impinge" , "Meet" , "Adjoin at one end" , "Touch, lean on" .)