光こう線せん束そく

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Meanings

1

noun

pencil of light rays; light beam

Technical term in optics for a narrow bundle of light rays, often used in physics and engineering contexts.

ray, light

線line, track

束bundle, sheaf, ream

光こう線せん
光線 means a single ray or beam of light, while 光線束 specifically refers to a bundle or pencil of rays.
光こう束そく
光束 is luminous flux, a photometric quantity, whereas 光線束 is a geometric optics concept describing a collection of rays.

Compound of 光線 (light ray) and 束 (bundle). The term is a direct calque of the English 'pencil of rays' used in optics.