Video jargon can quickly get complicated. But the basics of video are comparatively simple and easily learned, and the rest can follow from that.
‘HD’ stands for ‘high definition’ to distinguish it from older, lower resolution video standards. HD actually comes in two formats: standard HD has a resolution of 1280 x 720 pixels, full HD is 1920 x 1080 pixels. Both use the same 16:9 aspect ratio.
The aspect ratio of an image is the ratio of its width to its height. The larger the ratio, the ‘wider’ the image; the smaller the ratio, the ‘squarer’ the image.