light-gathering

The compound adjective 'light-gathering' is a modern technical formation built entirely from native English elements. Its first component, 'light,' descends from the Proto-Germanic leuhtam, which is itself derived from the Proto-Indo-European root leuk-, meaning "light, brightness." The second component, 'gather,' originates from the Proto-Germanic gadurōną, related to the idea of bringing together. The compound logically and transparently describes the core function of optical systems, such as telescope lenses or the retinas of nocturnal animals, by combining the ancient concept of illumination with the action of collection. Its meaning is entirely compositional, directly reflecting the literal sense of its parts.

Structure: light (illumination) + gathering (collecting) - light: From Old English lēoht, meaning "brightness, radiant energy." It functions as a noun used attributively to specify the type of energy being collected. - gathering: From Old English gaderian, meaning "to unite, join." The suffix -ing forms the present participle/gerund, here acting as an adjective meaning "the action of collecting."