480p

Definition:

The "480" part of 480p describes the number of vertical lines that make up a television or video signal. Most television or video signals are rated at 480, 720 or 1080. The more vertical lines that make up the picture, the crisper or higher definition the picture. The "p" following 480 indicates that the video display is constructed using a progressive scan method.

Many standard definition DVDs are published in a 480p format.

Here's a word you may not know...

aspect ratio

The aspect ratio of an image or other object is simply its width divided by its height. Traditional standard definition pictures have a 4:3 aspect ratio, where 4 represents the width and 3 represents the height. High definition pictures have a 16:9 aspect ratio.