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solid angle

solid angle

7.9
A measure that shows how much space an object appears to take from a point in three dimensions
  • noun
  • /ˈsɒlɪd ˈæŋɡəl/
  • Specialized
translation icon : ángulo sólido
  • In geometry, the solid angle is measured in steradians and represents the three-dimensional equivalent of a two-dimensional angle.
  • solid angle coverage
  • solid angle detector
  • large solid angle

Examples

  • The phase function defines the probability of photons being scattered into a unit solid angle.

    Academic text (1994)
  • The detector's solid-angle coverage of the target is very close to 4π.

    Academic text (2005)
  • It left about a third of the solid angle uncovered.

    Academic text (1995)
  • This Omega is the solid angle over which the source emits.

  • For nuclear collisions at RHIC, the intensity can be measured in terms of the number of particles (mostly pions) emitted into a given interval of solid angle.

    Academic text (2003)
  • When measuring the brightness of stars, astronomers often calculate the solid angle subtended by the star's light at the observer's location.

  • The solid angle formed by the intersection of three planes can be visualized as the region viewed from a point amidst those planes.

Synonyms

polyhedral angle
vssolid angle
  • Specialized
9.9

The space at a corner where three or more flat faces of a solid meet

is the measured three-dimensional angle for that region given in steradians

Surface Forms

solid angle singular
solid angles plural

Morphology

solid + angle

The term is a direct composition of 'solid' (three-dimensional/3D) and 'angle' (a measure between rays or lines), so a learner who knows both words can infer it refers to an angle in three-dimensional space; the precise technical definition and unit (steradians) are specialized but do not prevent the basic sense from being predictable. This geometric compounding is cross-linguistically common, making the expression transparently compositional for learners.

Etymology

Solid angle comes from imagining an ordinary angle but in space: picture a cone or a slice of the space that opens from one point and points outward. The word solid shows it is about space (not a flat surface) and angle describes how wide that cone is, so the term means 'how much of the space around a point is covered'.