The word "Aerodynamics" comes from two Greek words: aerios, concerning the air, and dynamis, meaning powerful.
Aerodynamics is the study of forces and the resulting motion of objects through the air.
Drag is the aerodynamic force resisting the motion of the object through the fluid. It is produced by front/rear pressure differences and the shearing between fluid and solid surface.
Lift is the aerodynamic force acting at right angles to the direction of motion of the object. It is produced by the interaction of the moving object and the fluid. This interaction leads to a pressure differential between the upper and lower surfaces of an object.
The nett effect of high pressure below and low pressure above will produce a force which sustains the object against descent due to gravity.