On what screens can I watch full HD video?

Question

YouTube

For example, YouTube has 1080p video resolution.
1) What does this mean? Video with 1920 width and 1080 height. Or 1080 width in this case?
2) Full hd video can only be watched on full HD screens? Is 1280x720 resolution no longer suitable?
p.s. sorry for these questions.

Answer 1

1) 1080p is the standard. Description is on the wiki. Quite in general - yes, this is generally 1920 * 1080
2) You can watch any video on any monitor - it will simply either compress or stretch the picture, which in one way or another will lead to artifacts.

Answer 2

If I'm not mistaken, then the screen resolution does not greatly affect whether you can watch fullhd. I watch 4k with my 1366x766px screen and nothing. It depends more on the video card (in my opinion), whether this resolution is supported or not.