(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 revert 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 will be fixed up; he will be all right for something, or what he has had will be over. —AcademyLevel IV Glossary