Did second check in English dictionary (6)
I believe the answer is:
echoed
'did second' is the definition.
(ie seconded)
'check in english dictionary' is the wordplay.
'check' becomes 'ch' (I've seen this in other clues).
'in' indicates putting letters inside.
'english' becomes 'e' (abbreviation).
'dictionary' becomes 'oed' (Oxford English Dictionary).
'e'+'oed'='eoed'
'ch' going into 'eoed' is 'ECHOED'.
(Other definitions for echoed that I've seen before include "Repeated a sound" , "Reverberated; repeated" , "Rang" , "said nothing original" , "Resounded" .)