So, what is memoization in software engineering?

Memoization is a fancy word for a simple concept: caching the result of a function so you don't have to calculate it again.

The function saves the result of the call when it finishes. If the function is called again with the same arguments, it recognizes that it has been called with those exact inputs before. It then simply returns the saved value instead of repeating the entire process, which could be computationally expensive.