A herma was a stone marker associated with Hermes in ancient Greek religion.
Hermas were typically rectangular pillars topped by a carved head, often representing Hermes, with a projecting phallus. They were placed beside roads, at boundaries, near entrances, and in other public or private locations. Their presence reflected Hermes’ connections with travel, protection, boundaries, fertility, and communication.
The plural form is herms. These markers were practical religious objects as well as works of sculpture. Because they stood at thresholds and crossroads, they were especially suitable symbols for a god who moved between places and social worlds.
In 415 BCE, Athens suffered the mutilation of its herms shortly before the Sicilian Expedition. The incident caused widespread alarm and became a major political and religious scandal. A herma is different from a stele, which is a broader category of upright stone monument without the characteristic head-and-pillar form.