Pronunciation: (hī"dru-pon'iks), [key]
—n. (used with a sing. v.)
the cultivation of plants by placing the roots in liquid nutrient solutions rather than in soil; soilless growth of plants. Cf. aeroculture, geoponics (def. 2).
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.