A public IP address is an address used in globally routable internet communication. The address a service sees can belong to a home connection, a shared provider arrangement or another intermediary, rather than one individual device. It can change over time and should be interpreted as connection information rather than a reliable personal identity.
A practical example
Several devices in a household can appear to a service through the same public IPv4 address while retaining different private addresses inside the home. Another household behind some provider arrangements may also share an outward-facing address through additional translation.
A common misunderstanding
A shared or changed public address does not automatically justify account sharing or establish a device limit. Subscription rules and network addressing are separate matters that need their own evidence.
Related terms
Stable technical definition. Editorial approach