/ Dictionary / Index M microfiber: Meaning and Definition of Find definitions for: mi•cro•fi•ber Pronunciation: (mī'krō-fī"bur), [key] a very fine polyester fiber, weighing less than one denier per filament, used esp. for clothing. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. microfauna microfibril Related Content Daily Word Quiz: careening Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language