What is the difference between a connector, jack, plug, and port?

Plug

The plug is part of a cable that connects into a port. The plug always connects to something else (e.g. a jack or port). For example, the most common plug is the power plug that connects your computer and monitor to a power source and allows it to turn on and boot. In the picture to the right, is an example of a traditional desktop power cord with a male plug end that connects to the wall socket and the female plug end that connects to the computer or monitor.

Connector

A connector is the unique end of a plug, jack, or the edge of a card that connects into a port. For example, all desktop computer expansion cards will have a connector that allows the card to be connected into a slot on the motherboard. When referring to cables, the connector is the end of the cable that connects into a port. For example, the end of a USB cable has a connector that allows it to connect into a USB port.

Port

The port will have either holes or a slot that matches the plug or card being connected into the port. You will always plug something into a port. In the picture to the right, is an example of a PS/2 port found on the back of computers that allows a keyboard and mouse with a PS/2 connector to be connected to the computer.

Note: There are also software ports, for example, port 80 is a network port that allows HTTP traffic (i.e. browsing the Internet) over a network.

Jack

A jack is similar to a port and is a hole or other connection that allows a compatible plug to be connected into the jack. You will always plug something into a jack. A jack is most often used when describing an audio jack.