/ Dictionary / Index F filamentous: Meaning and Definition of Find definitions for: fil•a•men•tous Pronunciation: (fil"u-men'tus), [key] — adj. composed of or containing filaments. pertaining to or resembling a filament. bearing filaments. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: filamentous (Thesaurus) filamentary filar Related Content Daily Word Quiz: tenacious Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language