What does application mean on a science project?

An application is how your science project could help someone in a real life situation. For example, a simple science project like which paper towel brand is stronger, the application for this project could be "If someone in the world wanted to soak up more with a paper towel, then that person could use 'this' brand instead of 'this' one because the other towel brand is stronger and soaks up more liquids.