Films half a dozen in Springfield bar (6)
I believe the answer is:
movies
'films' is the definition.
(I know this)
'half a dozen in springfield bar' is the wordplay.
'half a dozen' becomes 'VI' (Roman numerals for six - half a dozen).
'in' indicates putting letters inside.
'springfield bar' becomes 'moes' (I've seen this in another clue).
'vi' going inside 'moes' is 'MOVIES'.
(Other definitions for movies that I've seen before include "Cinema films" , "big-budget features" , "Flicks" , "Motion pictures" , "Films in America" .)