Hold about 50 to split 50-50 (5)
I believe the answer is:
halve
'split 50-50' is the definition.
I can't judge whether this definition defines the answer.
'hold about 50' is the wordplay.
'hold' becomes 'have' (synonyms).
'about' is an insertion indicator.
'50' becomes 'l' (Roman numeral).
'have' placed around 'l' is 'HALVE'.
'to' is the link.
Can you help me to learn more?
(Other definitions for halve that I've seen before include "split 50/50" , "Cut down substantially" , "Divide fifty-fifty" , "Bisect" , "Divide into two equal pieces" .)