Fasten or bind (3)
I believe the answer is:
tie
I believe this clue is a double definition.
'fasten' is the first definition.
(I know that fasten is a more specific form of attach)
'bind' is the second definition.
(I know that bind is a more specific form of attach)
(Other definitions for tie that I've seen before include "Bond; neckwear" , "Stalemate" , "Lace" , "'Fasten, with string say (3)'" , "sports match" .)