Question

What do we call the holes and slots at the back of computer system?

Answer 1

Those holes and slots at the back of your computer might be referred to as PORTS.

Moreover as far as ports are concerned you may come across many such ports, such as FireWire, Thunderbolt, and HDMI.

Answer 2

The holes and slots at the back of the computer system (more precisely on the back of the Central Processing Unit or CPU) are called ports.

Ports are the gateway in to and out of the computer and are mainly used for connecting various input or output devices. The name of network ports is also adapted from these physical ports since the network port also acts as a gateway in to and out of a host inside a network.