spherical angle
- noun
- /ˈsfɪrɪkəl ˈæŋɡəl/
- Specialized
- In spherical geometry, a spherical angle is defined as the angle formed by two intersecting arcs of great circles.
Examples
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The navigators used spherical angles to accurately plot their courses across the globe's surface.
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The geometry of a sphere starts with great circles and talks about spherical distances, spherical angles, your triangles, polar triangles.
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To calculate the area on a sphere, one must consider the spherical angle created by the curves of the great circles.
Surface Forms
Morphology
The meaning is directly compositional: 'spherical' (relating to a sphere) combined with 'angle' (a measure between lines) yields an angle on a sphere, so a learner who knows both words can infer the basic concept. While the precise mathematical detail about great circles is technical, the core idea (an angle defined on a spherical surface) is transparently derivable from the constituents.
Etymology
The noun spherical angle comes from looking at angles on a globe: spherical means 'round like a ball' and angle is the space between two lines. Imagine two curved lines on the ball that meet at one point — the space between them there is the spherical angle, so the term means the angle made by two arcs on the surface of a sphere.