A bright, harsh light or strong reflection that causes discomfort to the eyes; glare.
From Old Norse 'glarr' (gleaming). This word traveled through Scandinavian languages and entered English through maritime contact, originally describing the gleaming reflection of light on water.
Sailors have been complaining about glar for centuries—the sun bouncing off the ocean is blinding, which is why so many old sailing terms describe different types of glare and reflection.
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