Income
Middle English (in the sense ‘entrance, arrival’, now only Scots): in early use from Old Norse innkoma, later from in + come. The current sense dates from the late 16th century.
wiktionary
From Middle English income, perhaps continuing (in altered form) Old English incyme(“an in-coming, entrance”), equivalent to in- + come. Cognate with Dutch inkomen(“income, earnings, gainings”), German Einkommen(“income, earnings, competence”), Icelandic innkváma(“income”), Danish indkomst(“income”), Swedish inkomst(“income”).
etymonline
income (n.)
c. 1300, "entrance, arrival," literally "a coming in;" see in (adv.) + come (v.). Perhaps a noun use of the late Old English verb incuman "come in, enter." Meaning "money made through business or labor" (i.e., "that which 'comes in' as payment for work or business") first recorded c. 1600. Compare German einkommen "income," Swedish inkomst. Income tax is from 1790, introduced in Britain during the Napoleonic wars, re-introduced 1842; in U.S. levied by the federal government 1861-72, authorized on a national level in 1913.
