Individually

google

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late Middle English (in the sense ‘indivisible’): from medieval Latin individualis, from Latin individuus, from in- ‘not’ + dividuus ‘divisible’ (from dividere ‘to divide’).

wiktionary

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individual +‎  -ly

etymonline

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individually (adv.)

1590s, "indivisibly," from individual + -ly (2). Meaning "as individuals" is from 1640s.