To make bright or brighter; to illuminate or give light to something.
From 'em-' (to make or cause to be) combined with 'bright' (giving off light), from Old English 'beorht.' This follows the productive pattern of English intensifying verbs.
Modern LED technology literally 'embrightens' spaces more efficiently than old incandescent bulbs because they direct photons more precisely—but the basic goal humans have always had is the same: making darkness into light.
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