Ropes in fifty-one cats (9)
I believe the answer is:
lifelines
'ropes' is the definition.
The definition and answer can be both man-made objects as well as being plural nouns.
Maybe they are linked in a way I don't understand?
'fifty-one cats' is the wordplay.
'fifty' becomes 'li' (I've seen this in other clues).
'one cats' becomes 'felines' (I've seen this in another clue).
'li'+'felines'='LIFELINES'
'in' is the link.
Can you help me to learn more?
(Other definitions for lifelines that I've seen before include "May 23 [COME TO THE RESCUE], these" , "Means to rescue" .)