Clove hitch or butterfly loop (4)
I believe the answer is:
knot
I believe this clue is a double definition.
'clove hitch' is the first definition.
(I know that clove hitch is a knot)
'butterfly loop' is the second definition.
(I know that butterfly loop is a knot)
(Other definitions for knot that I've seen before include "Fastening such as reef or granny" , "Nautical mile, loosely" , "Tie cord - lump in timber" , "See 2" , "Assemblage" .)