An Interface address is an interface (network )address, a network interface address, it's just a network address that belongs to an interface. Though almost all belong to an interface if they're being used. The term you've used brings up an important point.
Almost all network addresses e.g. IP addresses, belong to a network interface. (if they're used at all). Any device with an IP Address, has an IP Address on an interface.
A network interface is the electronics of the part where the network cable connects to - the controller there. Or where the wireless device connects to. NIC stands for network interface controller or network interface (controller) card. WNIC is wireless network interface controller or wireless network interface (controller) card.
IP Addresses belong to network interfaces, not to the computer itself. You don't ping a computer, you ping a computer's network interface.
Even if you ping 127.0.0.1 , 127.0.0.1 is known as the loopback interface. So even that is known as an interface.
A computer could have a NIC with many ethernet sockets, many network interfaces and each one with a different IP Address, see the IP Address belongs to an interface. And electronically, if you ping a computer, you're actually pinging in particular, a or the network interface on the computer.
There aren't many examples of IP Addresses that do not belong to an interface. An IP Address you haven't assigned to an interface (so it isn't assigned to a device, because IPs aren't exactly assigned to devices, only to interfaces of devices). The network address I suppose does not and even cannot belong to any interface(though I may be wrong on that). And the broadcast address e.g. 255.255.255.255 designed to be sent to all interfaces, no interface would have that address.