/ Dictionary / Index U underdrain: Meaning and Definition of Find definitions for: un•der•drain Pronunciation: (n.un'dur-drān"v.un"dur-drān'), [key] — n. a drain placed beneath the surface of cultivated fields, streets, etc. —v.t. to equip or supply with an underdrain or underdrains. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. underdraft underdrainage Related Content Daily Word Quiz: fabricate Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language