herm, in 6th-century Greek art, vertical pillar surmounted by a bearded human head and often having a phallus below. These structures were considered sacred to Hermes. They were placed on street corners in Athens and used outside the city as milestones. By the end of the Hellenistic era the form was employed for portraiture.

Herm: see Channel Islands.

In Greek religion, a sacred stone object connected with the worship of Hermes. Herms were used as cult objects, for milestones, and for boundary markers. In time, these stones were replaced by pillars topped with a likeness of the head of Hermes or by statues of the god. In Roman sculpture the heads of Jupiter or the forest god Silvanus were often substituted.

Learn more about herm with a free trial on Britannica.com.