Automatic Private IP Addressing

An addressing system in place to use special IP addresses when something goes wrong with the DHCP server or with the host that needs it.

APIPA addresses always begin with 169.254.x.x.

APIPA is triggered when a DHCP server takes too long to offer an IP address lease to the client.

Apparently the name APIPA is Microsoft-only. Official documentation call this protocol IPv4 Link Local (IPv4LL).