Additional means extra or more than what you already have. When you ask for additional help with your homework, you're requesting more assistance beyond what you've gotten so far. When a recipe calls for an additional cup of flour, you need to add another cup on top of what you've already measured.

The word suggests something being added to an existing amount or situation. A teacher might assign additional practice problems to students who want more challenge. A family planning a road trip might pack additional snacks in case they get hungry between stops. During a game that's tied at the end, teams might play additional innings or quarters to determine a winner.

Notice that additional always refers to something beyond the original or expected amount. If your allowance is five dollars and you earn an additional three dollars by doing extra chores, you now have eight dollars total. The three dollars are additional because they come on top of your regular five.

You might also hear people say “in addition,” which means something similar: In addition to studying math, you also need to practice your spelling words. The phrase signals that something more is coming.