blanket

Blanket comes from Middle English blanket, borrowed from Old Northern French blanket/blancet, a diminutive of blanc meaning 'white' — literally 'that which is white,' used for white woollen cloth or flannel. Blanc itself traces to a Germanic root, the same one behind Old English blanca, 'white horse.'

The French word for white woollen cloth was likely also shaped by Old English hwītel, a native word for 'blanket' or 'cloak' built from hwīt ('white') plus a diminutive suffix — so English speakers already had a near-identical idea in their own tongue. Eventually the French-derived blanket pushed out that native word, whytel, from everyday use.

Blanket shares its 'white' root with blank, both descending from the same Germanic source for whiteness or blankness. It's also quietly related to whittle, which comes from that displaced Old English word hwītel for a blanket or cloak.