/ Dictionary / Index S sillimanite: Meaning and Definition of Find definitions for: sil•li•man•ite Pronunciation: (sil'u-mu-nīt"), [key] — n. a mineral, aluminum silicate, AlSiO, occurring in the form of long, slender, and often fibrous crystals. Also called Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. Silliman Sills Related Content Daily Word Quiz: paradox Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language