An outgrowth is something that develops or grows out of something else, like a natural result or side effect. When your school starts a recycling program and then students form an environmental club, that club is an outgrowth of the original program. It wasn't planned from the start, but it grew naturally from the idea of caring for the environment.

You'll often see this word when people explain how one thing led to another. The internet was an outgrowth of military research into connecting computers. Your friendship with someone might be an outgrowth of sitting next to them in class. A city's sports teams might be an outgrowth of its strong tradition of athletics in schools.

In biology, an outgrowth can be a literal physical growth extending from something else, like a branch growing out from a tree trunk or a coral formation extending from a reef. But people also use outgrowth to describe how ideas, organizations, or situations develop from earlier ones. When you hear someone say “this was a natural outgrowth of our earlier work,” they mean it developed logically and organically from what came before, not that anyone forced it to happen.