Spark second girl to secure one collection of books (9)
I believe the answer is:
scintilla
'spark' is the definition.
(I've seen this before)
'second girl to secure one collection of books' is the wordplay.
'second' becomes 's' (common abbreviation).
'girl' becomes 'cilla' (woman's name).
'to secure' is an insertion indicator.
'one' becomes 'i' (roman numeral).
'collection of books' becomes 'nt' (New Testament).
'i'+'nt'='int'
'cilla' placed around 'int' is 'cintilla'.
's'+'cintilla'='SCINTILLA'
(Other definitions for scintilla that I've seen before include "little bit" , "Slight amount" , "A spark; a trace" , "Tiny, scarcely detectable amount" , "Tiny hint, trace" .)