/ Dictionary / Index M mainly: Meaning and Definition of Find definitions for: main•ly Pronunciation: (mān'lē), [key] — adv. chiefly; principally; for the most part; in the main; to the greatest extent: Our success was due mainly to your efforts. The audience consisted mainly of students. greatly; mightily; abundantly. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: mainly (Thesaurus) mainliner mainmast Related Content Daily Word Quiz: stringent Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language