/ Dictionary / Index V vasoactive: Meaning and Definition of Find definitions for: vas•o•ac•tive Pronunciation: (vas"ō-ak'tiv, vā"zō-), [key] — adj. Physiol., Pharm. of or pertaining to a substance, drug, or event that changes the diameter of a blood vessel. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. vaso- vasoconstriction Related Content Daily Word Quiz: philtrum Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language