We just called 'em Bois d'Arc trees growing up. Though I did occasionally hear them called horse apple and hedge apple. The wood is really good for corner posts too. One day, back in the late Eighties I was driving to a lease and came upon an accident. A pickup had run off the road and waylaid the corner of a fence along a section line. I stopped and made some calls to help out. My cell phone was huge back then LOL. Anyways the rancher came by and finally the state patrol but I recall mentioning it seemed impossible that the corner post be in one piece. The ground was wet and the truck run over the post pushing up the soil on the back side. The rancher told me that the post had been there since before Oklahoma was a state and that it was made of Bois d'Arc.

The name Bois d'Arc is French for "bow wood" and the wood was prized by Native Americans for making longbows and also arrows.