Greek Pillar is a term used to describe a type of monument or structure that was popular in Ancient Greece. It typically consists of a tall, vertical stone slab with an inscription or relief carving on it. The two most common terms for this type of structure are Stele and Stela, both of which have five letters. Stele is the more general term, while Stela is specifically used to refer to a pillar with an inscription or relief carving.