over-under: Meaning and Definition of

o•ver-un•der

Pronunciation: (ō'vur-un'dur), [key]
— adj.
  1. (of double-barreled firearms) with one barrel mounted over the other.
—n.
  1. such a firearm.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.