What does angle of entry mean?

The definition of angle of entry

An”gle of en”try. (AÃ«ronautics)

The angle between the tangent to the advancing edge (of an aÃ«rocurve) and the line of motion; — contrasted with angle of trail, which is the angle between the tangent to the following edge and the line of motion.

The angle between the tangent to the advancing edge (of an aÃ«rocurve) and the line of motion; — contrasted with angle of trail, which is the angle between the tangent to the following edge and the line of motion.