The phrase "based on" is used to indicate that something is founded or derived from something else. It often implies that a decision, idea, or work is influenced by evidence, prior understanding, or factual information. For example, when a movie is "based on" a book, it means that the movie uses the book as a source or inspiration for its story.
The phrase "based on" comes from the word "base," which originates from the Latin word "basis," meaning "foundation." The evolution of the word includes influences from Old French "base," which means "bottom" or "foundation."