Separate the ropes, partly for fastening (6)
I believe the answer is:
tether
'fastening' is the definition.
The definition and answer can be both man-made objects as well as being singular nouns.
Maybe there's an association between them I don't understand?
'separate the ropes partly' is the wordplay.
'partly' indicates the answer is hidden within the clue (part of the clue is used).
'TETHER' can be found hidden inside 'separate the ropes'.
'for' is the link.
Can you help me to learn more?
(Other definitions for tether that I've seen before include "Bond" , "Hold by a rope" , "Restraining rope for animals" , "Rope for hobbling animal" , "Rope keeping animal from straying" .)