Introduction in favour of record, say (8)
I believe the answer is:
prologue
'introduction' is the definition.
(I know that prologue is a type of introduction)
'in favour of record say' is the wordplay.
'in favour of' becomes 'pro' (being pro a particular cause).
'record say' becomes 'logue' (I am not sure about this - if you are sure you should believe this answer much more).
'pro'+'logue'='PROLOGUE'
Can you help me to learn more?
(Other definitions for prologue that I've seen before include "Introductory passage" , "Preface to a literary work" , "Dramatic preface" , "Introductory piece" , "Start to play" .)