Size of a book or volume on love (6)
I believe the answer is:
quarto
'size of a book' is the definition.
'quarto' can be an answer for 'book' (I've seen this before). I am not sure about the 'size of a' bit.
'volume on love' is the wordplay.
'volume' becomes 'quart' (I've seen this in other clues).
'on' says to put letters next to each other.
'love' becomes 'o' (love means zero in tennis).
'quart'+'o'='QUARTO'
'or' acts as a link.
Can you help me to learn more?
(Other definitions for quarto that I've seen before include "Book size resulting in folding one sheet four times" , "Twice-folded paper size" , "Publishing term, four leaves are formed from one sheet" , "Book page size" , "Ten-by-eight inch paper" .)