/ Dictionary / Index A active transport: Meaning and Definition of Find definitions for: ac'tive trans'port Pronunciation: [key] the movement of ions or molecules across a cellular membrane from a lower to a higher concentration, requiring the consumption of energy. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. active sun activewear Related Content Daily Word Quiz: fresco Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language