adv. 25B6; adverb MAINLY, in the main, primarily, principally, predominantly, mostly, for the most part; usually, habitually, typically, commonly, generally, on the whole, largely, by and large, as a rule, almost always.
CHIEFLY
Meaning of CHIEFLY in English
Concise Oxford thesaurus English vocabulary. Краткий оксфордский словарь английского языка тезаурус. 2012