Aeronautical means related to the science, engineering, and practice of flight through Earth's atmosphere. When something is aeronautical, it has to do with designing, building, or operating aircraft like airplanes, helicopters, and gliders.

Aeronautical engineers figure out how to make aircraft safe, efficient, and capable of incredible feats. They calculate how wings should be shaped to generate lift, how much fuel a plane needs to cross an ocean, and how to build structures strong enough to handle the forces of flight. The Wright brothers were aeronautical pioneers who solved the mystery of controlled, powered flight in 1903.

You'll often see aeronautical paired with other words: an aeronautical chart shows pilots the information they need to navigate, while aeronautical regulations are the rules that keep air travel safe. Universities offer degrees in aeronautical engineering for students who want to design the next generation of aircraft.

The word specifically refers to flight within Earth's atmosphere. Once you leave the atmosphere and head into space, you're in the realm of astronautics instead. So an aeronautical engineer might design a sleek passenger jet, while an astronautical engineer works on rockets and spacecraft.