An alembic is like a magical container that can hold really, really complex things that you drew on your computer. When you draw something on the computer, it's made up of lots and lots of tiny little bits that work together to make the picture. But sometimes, when you have a REALLY complicated picture with lots of little bits, your computer can't handle it and it gets all slow and glitchy. That's where the alembic comes in!
You can take all those little bits of your picture and put them inside the alembic so your computer doesn't have to work as hard to show your picture. And the best part is, you can take your alembic to other computers and they will still be able to show your picture just like you made it - even if they don't have all the same fancy computer programs you used to create it. It's like carrying your picture in a special box that keeps it safe and lets it travel anywhere you want to show it off!