The plural of stele is stelae.
Stelae were used as grave markers, for dedication, commemoration, and demarcation. They were usually retangles carved in relief.
One of the most famous stelae is the diorite stele of the Code of Hammurabi. At the top of this stele, Hammurabi faces the sun god Shamash. Another important stele is the Novilara Stele, which holds a 12-line inscription in the North Picene language.