/ Dictionary / Index P phthiriasis: Meaning and Definition of Find definitions for: phthi•ri•a•sis Pronunciation: (thī-rī'u-sis, thi-), [key] — n. crab lice infestation. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. phthiocol phthisic 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