/ Dictionary / Index P pilonidal: Meaning and Definition of Find definitions for: pi•lo•ni•dal Pronunciation: (pī"lu-nīd'l), [key] — adj. Pathol. noting or pertaining to a growth of hair in a dermoid cyst or in the deeper layers of the skin. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. pilon Pilos Related Content Daily Word Quiz: penchant Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language