Definition
The figure formed by two straight lines or surfaces that meet at a common point, called the vertex. The size of an angle is the amount of rotation between the two lines, measured in degrees, minutes, and seconds, or in radians.
Plain English
The opening between two lines that meet at a point. How wide that opening is gets measured in degrees.
Context Anchor
Pilots see this word in descriptions of turns, climbs, descents, runway alignment, and aircraft position relative to the horizon or airflow.
Derivation
From the Latin angulus, meaning 'corner.' An angle is literally the corner formed where two lines come together.
Why Pilots Care
Almost every aerodynamic and navigation concept in aviation is described as an angle. Understanding what an angle actually is -- the measured opening between two reference lines -- is the foundation for understanding terms like angle of attack, bank angle, and pitch angle.
Intuition Check
Angle does not just mean a sharp corner. In aviation, it usually means a measured difference between two directions or surfaces.
Example Sentence 1
The wing meets the fuselage at a small upward angle, called the angle of incidence.
Example Sentence 2
A higher angle between the wing chord and the airflow increases lift up to the critical point.