What does the 'i' in 1080i stand for?

Within the designation "1080i", the i stands for interlaced scan. A frame of 1080i video consists of two sequential fields of 1920 horizontal and 540 vertical pixels. The first field consists of all even-numbered TV lines and the second all odd numbered lines.

What is the difference between 1080p and 1080i?

We’ll start with the abbreviations — 1080p is short for 1080 progressive scan, whereas 1080i is short for 1080 interlaced scan. The difference between these two formats is how they’re displayed on your screen. In an interlaced scan, the image is displayed by illuminating odd and even pixel rows in an alternating fashion.

What is the scan type used in 1080i?

[In 1080i] all the odd lines are displayed, followed by all the even lines. This means that only 1/2 the resolution (540 lines or pixel rows) is displayed on the screen at any give time – in other words, only 540 pixel rows are displayed at any given time.