In simple terms, the aspect ratio of a movie is how wide the frame of the movie is versus how tall it is, usually expressed as a ratio. For example, most TVs and computer monitors are 1.77:1 (more ...

Confused why there are black bars on the top and bottom (or sometimes on the sides) of your TV? It's not your TV. Well, not really. Here's all you ever wanted to know about aspect ratios.