Additionally means in addition to what has already been mentioned, or as something extra. When you write a report and say “Additionally, we should consider the weather,” you're adding another point to think about. When a teacher says “Do problems 1 through 10, and additionally, try the bonus problem,” they're asking you to do something on top of the regular assignment.

You'll often see additionally at the start of a sentence when someone wants to tack on one more idea. If a friend is explaining why they liked a book and says, “The story was exciting, the characters were interesting, and additionally, the illustrations were beautiful,” they're stacking up reasons, adding that third point to strengthen their case.

Additionally works like words such as furthermore, moreover, or also, but it sounds more formal. You might use it in school writing or presentations rather than casual conversation. Instead of saying “additionally” to a friend, you'd probably just say “also” or “plus.”