/ Dictionary / Index C claustrum: Meaning and Definition of Find definitions for: claus•trum Pronunciation: (klô'strum, klou'-), [key] — pl. claus•tra barrier. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: claustrum (Thesaurus) claustrophobic clausula Related Content Daily Word Quiz: philtrum Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language