An ambulance (noun) is a battle lance that can be wielded equally well with either hand. This, of course, assumes that you are equally dexterous with both hand. Otherwise, to avoid death or other negative impacts on your social and sex lives, it’s best to fight battles with an ambulance, or any type of lance for that matter, using your dominant hand. Better yet, avoid battles altogether.
In truth, unless they have any fancy curves or awkward doodads, because of their normally perfect symmetry, most battle lances can be wielded equally well with either hand (again assuming equal dexterity with both hands). The Association of Battle Lance Makers (ABLM) came up with the word ambulance solely as a marketing contrivance designed to extract a premium price for their members’ lances.
This plan followed from the widely respected marketing rule that states, “The market is composed of mostly suckers who will fall for just about anything if you provide a legitimate sounding name and narrative.” It’s not an elegantly stated rule, but following it can be very profitable for marketers.