The word "school" itself is a complete word with its own meaning. It's not formed by combining a prefix and a root word.
However, there are some related words that use prefixes:
* Preschool: This refers to a school for young children before they enter primary school. "Pre" means before.
* Interschool: This refers to something involving multiple schools. "Inter" means between.
* Post-school: This refers to activities or programs that happen after someone has finished school. "Post" means after.
Let me know if you have any other word-related questions!