Meaning

noun bedding that keeps a person warm in bed

noun anything that covers

noun a layer of lead surrounding the highly reactive core of a nuclear reactor

originInherited from Middle English blanket, blonket, blaunket, from Old Northern French blanket, blancet (“white horse", also "white woollen cloth or flannel; a type of jacket”, literally “that which is white”) (whence Modern French blanchet), diminutive of blanc (“white”), of Germanic origin (compare Old English blanca (“white horse”); see more at blank). Furthermore, the sense "white woollen cloth"…

Etymology from Wiktionary, CC BY-SA 3.0