Binary

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late Middle English (in the sense ‘duality, a pair’): from late Latin binarius, from bini ‘two together’.

wiktionary

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From Late Latin bīnārius(“consisting of two”), from Latin bīnī(“two-by-two, pair”).

etymonline

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binary (adj.)

"dual, twofold, double," mid-15c., from Late Latin binarius "consisting of two," from bini "twofold, two apiece, two-by-two" (used especially of matched things), from bis "double" (from PIE root *dwo- "two"). Binary code in computer terminology was in use by 1952, though the idea itself is ancient. Binary star in astronomy is from 1802.