/ Dictionary / Index P pycno-: Meaning and Definition of Find definitions for: pycno- Pronunciation: [key] a combining form meaning “dense,” “close,” “thick,” used in the formation of compound words: pycnometer. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. pycnium pycnometer Related Content Daily Word Quiz: secular Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language