income

From Middle English income, which perhaps continues in altered form the Old English incyme, meaning "an in-coming, entrance." It's built from in- plus come — literally, something that comes in.

The facts given don't trace a specific shift in meaning, only the word's descent from a term meaning "entrance" or "in-coming" to its modern sense.

It shares its root sense with cognates across Germanic languages: West Frisian ynkommen, Dutch inkomen, German Einkommen, Danish indkomst, and Swedish inkomst all carry the same idea of money coming in.