(of double-barreled firearms) with one barrel mounted over the other.
such a firearm.
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019
Examples from the Web for over-under
Contemporary Examples of over-under
It is really matter of serendipity that Michael Vick has changed, and the over-under on bamboozlement is still 50 percent.Time to Forgive Michael Vick
December 23, 2010
(of a two-barrelled firearm) having one barrel on top of the other
an over-under firearm
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012