I've learned something! What Is the Difference Between a Monolid and a Doublelid?

On Tuesday, Beautylish featured a tutorial titled, "2 Minute Smokey Bronze - Quick Everyday Eye Tutorial (Great for MONOLIDS TOO)". I've been taking longer and longer to apply my makeup lately, so I was instantly interested by the title, claiming it only took 2 minutes. Right from the very beginning of the video, the host Holly Ann-AeRee N. started saying it's great for monolids as well as double-lids. Even though the word was in the video title, I didn't catch it right away. She mentioned it a few more times before beginning the tutorial, which actually made me stop and think, "What the heck is a monolid?!" It sounded like it should have been self explanatory  but  I still didn't get it, so I decided to look it up.

I've discovered, a monolid is where when a person's eyes are open, you cannot see they're actual eyelid. Their eye opens up and you pretty much just see their lash line and the skin under the brow bone. A very common example of this can be found in Asian eyes.

A double-lid, is where you can see a person's eyelid when their eyes are open, like mine.

Before hearing this, I never knew the style of eyes had different terms. I thought everyone has eyelids and they're called, well, eyelids! I can understand how which type of eye shape you have may determine the styles of makeup you wear, so it could be helpful to recognize those differences. Apparently having surgery to have double-lids is popular as well (read about it here). To that I say, women, you are beautiful just the way you are - whether that be mono- or double-lided. You don't need surgery!

Am I the only one who didn't know what these terms meant? Have I taught you something today? Let me know! I'd love some feedback :)