Work Hot, defined:
When someone appears to be hot, but upon further investigation, you realize they are not really hot; they just appear to look hot in the context of the office.

People can be “Work Hot” but not hot in real life. It is a byproduct of being bored here in the office, plus the limited supply of humans in the confined space, plus more boredom.

Example:
Dude: That intern is hot.
Dude’s coworker: No, dude. She’s not. Look closer.
Dude: Oh, dang, you’re right. She’s just Work Hot.

Work Plain is another phenomenon, whereby someone appears to be average at work, because they dress down and are sabotaged by the fluorescent lights. Then you see them out in public and become entranced by their striking good looks and wonder how you never noticed them at work before. But then the next day at work, they are Work Plain again.
Note: This is a VERY, VERY RARE phenom, so don’t get all excited and think that your Work Hot coworker might actually be Work Plain and even better looking than you are imagining that they are even though they’re not because it’s just office-altered. See, it is very complicated. This is why we do not advise dating someone you work with. It is difficult to know what you are getting into.