/ Dictionary / Index P pond scum: Meaning and Definition of Find definitions for: pond' scum" Pronunciation: [key] any free-floating freshwater alga that forms a green scum on water. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. pondok pondweed Related Content Daily Word Quiz: neologism Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language