The following is a simple identification chart that people who are unfamiliar with video connector terminology can use to identify four of the most common video connectors. They are arranged in more or less in order of oldest to newest as I have seen them common in harware around work and home.

VGA

Around since 1987, this is the most common connector for desktop workstations and older laptops. On Dell computers VGA cables and connectors are consistently colored blue. Thinner laptops and Apple hardware may not have the VGA connector.

DVI

On Dell computers DVI cables and connectors are consistently colored white. I am not aware of any laptops with DVI connectors.

HDMI

Probably most familiar from home audio visual equipment (game consoles, disc players, televisions, etc.), these connectors allow transmission of audio and visual information over a single, relatively thin cable.

DisplayPort

In the same way USB connectors have changed shape and sizes over the years, DisplayPort connectors come in a variety of shapes and sizes depending on vendor and physical constraints of hardware. Like HDMI, DisplayPort is capable of transmitting audio as well as video information.