[Ref. Pilot’s Handbook of Aeronautical Knowledge, FAA-H-8083-25B Page 7-4]
Angle of Incidence (AoI) of blade (= pitch) ≠ blade angle
However, pitch is largely determined by blade angle and so two terms are often used interchangeably – again, “Pitch” is not exactly the “blade angle”!
“Pitch” is the distance in inches, which the propeller would screw through the air in one revolution if there were no slippage
What’s “Blade angle”?
“Blade angle“, usually measured in degrees, is the angle between the chord of the blade and the plane of rotation