No. They're called "retina" because the people who name things at Apple are professionally focused on deceiving you. What a surprise.

I've seen lots of articles about this over time, here's one I googled just now:

http://www.cultofmac.com/173702/why-retina-isnt-enough-featu...

Combine this with what jamesaguillar already said, about wanting a larger screen and also wanting high PPI, and why wouldn't you want higher res?

> I thought 4k was just for large tvs

4k is nothing more than the double resolution from 1080p

> can you tell a difference over a retina display?

A 21" Retina Display iMac would be 4k (the current 21" iMac is 1920x1080). A 27" Retina Display iMac would be way beyond 4k (it would have a 5120x2880 display)

> Aren't they called retina because that's the most your eye can see?

That's more of a marketing moniker and incomplete. The original point/qualifier is that they fall beyond the eye's angular resolution so you can't "see" individual pixels anymore. That's not "the most your eyes can see" though, many arthropods create details & colors through nanometric structures.

Actually, 4k screens are useless for TVs (despite what all the TV manufactures want you to believe), since you generally sit so far away from them. A 4k monitor would be very nice, since it would be large but still very high DPI (ie, "Retina").

My understanding is that a 4k 30" monitor is a retina display at 30 inches. I know that I can see pixel edges on my Dell Ultrasharp, and it's 2560x1440. My guess is that I would not be able to see pixel edges if the resolution was quadrupled (4k).