Where does “why” come from?

Why comes from Middle English why, from Old English hwȳ, from Proto-Germanic hwī, from Proto-Indo-European kʷey, ultimately from Proto-Indo-European só.

why (English): For what cause, reason, or purpose; For which...

Definitions

  1. For what cause, reason, or purpose; For which...

Ancestry of “why”, step by step

why traces back through two separate lines of ancestry.

via Middle English why

StepLanguageWordMeaning
1Middle Englishwhy—
2Old Englishhwȳwhy
3Proto-Germanichwīhow, with what, by what means; instrumental of...
4Proto-Indo-Europeankʷey—
5Proto-Indo-Europeankʷisinterrogative, relative stem; who, what;...

via English quey

StepLanguageWordMeaning
1EnglishqueyA heifer
2Middle EnglishquyeA heifer young female cow
3Old Norsekvígaheifer, young cow
4Proto-Germanic*kūīgǭ—

Words derived from “why”

Every word from Proto-Indo-European kʷis →Every word from Proto-Indo-European kʷey →Every word from Proto-Germanic hwī →