What the heck is a Jellicle?

Jason and I had a date night a couple nights ago. He got $5 tickets to Cats at a theater downtown. I like the song "Memory" and other Andrew Lloyd Webber music, so I figured it would be great.

 I'm not entirely sure what I was expecting, but it wasn't that. The musical was seriously just a bunch of people dressed as cats dancing on stage while singing about different types of cats. The theater cat. The train cat. The thief cat. The magician cat. The ladies' man cat (who did altogether too much gyrating). And how all of them were going to the Jellicle ball because they were Jellicle cats. I don't even know what that means. Then at the end, one cat gets chosen to be reborn and is taken up by a spaceship. For real. The dancing was pretty spectacular though. And the cat who sings "Memory" was pretty awesome. It was worth just hearing that sung live. But seriously? How did a show like that run on Broadway 7,485 times?