What is aer?

Aer is a prefix that means "air" or "related to air". It is commonly used in words related to aviation, such as aerodynamics (the study of objects moving through air), aeroplanes (aircraft), aerospace (the branch of technology and industry concerned with aviation and space travel), and aeronautics (the science or art of flight). The term "aer" also has roots in ancient Greek, where it means "atmosphere" or "the upper air".