The legs of the eleven (4)
I believe the answer is:
ones
'the legs' is the definition.
Although both the answer and definition are plural nouns, I cannot see how they can define each other.
'of the eleven' is the wordplay.
'of' becomes 'o''.
'the eleven' becomes 'nes' (I can't justify this - if you can you should believe this answer much more).
'o'+'nes'='ONES'
Can you help me to learn more?
(Other definitions for ones that I've seen before include "1 & 1 & 1" , "Singles" , "Individuals" , "Units" , "(Of ship) returning to port of origin" .)