Have you ever written something by hand or drawn a picture on a piece of paper? Well, that piece of paper with your writing or drawing is called a manuscript!
A manuscript is usually a bunch of papers that someone writes on or draws on. It can be a story, poem, letter or even something called a "script" which is what people use to make movies or plays.
There are many different ways people write their manuscripts. Some people use really fancy pens, some people use pencils and some people even use computers!
So, a manuscript is really just a fancy name for a piece of paper with writing or drawings on it. And sometimes, the words and drawings on a manuscript can become very famous and important to many people!