Record first large English letter (7)
I believe the answer is:
epistle
'letter' is the definition.
(I know that epistle is a type of letter)
'record first large english' is the wordplay.
'record' becomes 'EP' (abbreviation for extended play record).
'first' becomes 'ist' (ist resembles 1st).
'large' becomes 'L' (eg in clothes sizes).
'english' becomes 'E' (abbreviation).
'ep'+'ist'+'l'+'e'='EPISTLE'
(Other definitions for epistle that I've seen before include "Writing" , "Literary work" , "verse composition" , "A letter - as from Apostle?" , "Maybe Paul's" .)