system
A chat on subreddit /r/pcmasterrace
human
Actually, 1080p *is* a 2K resolution.

4K is called 4K because it is **3840** x 2160 pixels. 3.8K is rounded to 4K in this case.

1080p is exactly half as wide and half as tall. It's **1920** x 1080 pixels. 1.9K is closer to 2K than 3.8K is to 4K.

This is also how the term was used in the film industry.

Calling 1440p 2K is something that monitor marketing made up.
gpt
In film and video production, 3840x2160 is actually called UHD, 4k is reserved for 4096x2160. When we're talking to clients and sometimes even amongst ourselves, UHD is often referred to as 4k simply because the difference between the two are so negligible, and 4k is a more common shorthand. However if shopping for a camera, it would be considered false advertising and misleading if a 3840x2160 camera was sold as "4k" because it's actually not