(slang) an artillery term. A gun, after it fires, is said to go out of battery, which is to say, it recoils. Then after it is fired it is supposed to go back to battery, which is sitting the way you see them in photographs. It is used as a slang term to indicate somebody who is now fixed up; he will be all right for something, or what he has had will now be over. —SHSBC Binder 24 Approved Glossary