By and large (6)
'by and large' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for as a rule that I've seen before include "Usually, in general" , "Mainly" , "Generally, normally" , "how one might take a calibrated rod" , "26 [NORMALLY]" .)
(Other definitions for as a general rule that I've seen before include "usually" , "for the most part" , "Normally" , "emulate Franco?" .)
'by and large' is the definition.
(synonyms)
This is the entire clue.
(Other definitions for mostly that I've seen before include "On the whole" , "In the main, nearly all" , "For the greater part; usually" , "In large part" , "More often than not" .)