Sideburns

google

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late 19th century: originally burnside, from the name of General Burnside (1824–81), who wore sideburns.

wiktionary

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Reformed from burnside, named after American Army general Ambrose Burnside (1824–1881), noted for his unusual beard.

etymonline

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sideburns (n.)

1880, American English, alteration of burnsides (q.v).