Ingress

Ingress refers to the act of entering or the permission to enter a place. In architectural and security contexts, it describes routes into a building or area, and the related concept of egress for exit pathways. The term is used in planning, safety regulations, and access control to distinguish entry from exit.

In computing and networking, ingress denotes data or traffic that enters a network, host, or system from an external source. Ingress filtering, firewalls, and intrusion-prevention systems focus on controlling or monitoring such traffic. In Kubernetes and other cloud-native environments, Ingress is a resource that defines rules for external access to services within a cluster, typically via HTTP, often implemented by an Ingress controller.

In astronomy, ingress describes the onset of an occultation or transit, when a celestial body begins to move onto the disk of another body, such as a planet starting to cross in front of its star. The complementary term is egress, marking the end of the event.

In popular culture, Ingress is a 2013 augmented reality mobile game developed by Niantic. Players capture portals and interact with geographic locations as part of a global competition between factions. The game helped popularize location-based and augmented-reality gaming.

The word ingress comes from Latin ingressus, from ingredi “to go in,” and entered English through legal, architectural, and scientific usage. It is commonly contrasted with egress, from egressus, to go out.