What does Co-Witness mean? Posted March 27, 2008 in Optics by Steve Johnson with 5 CommentsTags: Co-Witness, jargon, misc, Sights and Optics Apparently it refers to the use of a electronic sight along with backup iron sights. I was aware of the concept but not the word. A “Co-Witness” AR from eguns.com Traction Control explains. Win the new Springfield Armory XD-9 Mod.2 TFB's first ever gun giveaway.