Chapter about origin of wedding band (4)
I believe the answer is:
crew
'band' is the definition.
(I've seen this before)
'chapter about origin of wedding' is the wordplay.
'chapter' becomes 'c'.
'about' becomes 're' (regarding**).
'origin of' says to take the initial letters.
The initial letter of 'wedding' is 'w'.
'c'+'re'+'w'='CREW'
(Other definitions for crew that I've seen before include "Was exultant" , "band" , "Squad" , "emulated cocks" , "Company working together" .)