/ Dictionary / Index P planiform: Meaning and Definition of Find definitions for: pla•ni•form Pronunciation: (plā'nu-fôrm", plan'u-), [key] — adj. having a flattened shape, as an anatomical joint. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. plani- planify Related Content Daily Word Quiz: cygnet Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language