Where does “whereby” come from?

Whereby is an English compound formed from the preposition by and the relative pronoun where, both descending from Old English be and hwær respectively.

whereby (English): By what, in which direction; how; By which;...

Definitions

  1. By what, in which direction; how; By which;...

Ancestry of “whereby”, step by step

whereby traces back through two separate lines of ancestry.

via English by

StepLanguageWordMeaning
1EnglishbyNear or next to; From one side of something to...
2Middle Englishbybe
3Old Englishlullaby!; near, by; by, near, around
4Proto-West Germanicby, at; near, around
5Proto-Germanicbiby, at; near, around
6Proto-Indo-Europeanh₂m̥bʰiaround, on either side of, about; in exchange...
7Proto-Indo-Europeanh₂n̥tbʰi
8Proto-Indo-Europeanh₂éntsforehead; front
9Proto-Indo-Europeanh₂ent-face; forehead; front
10Proto-Indo-Europeanh₂en-on, onto

via English where

StepLanguageWordMeaning
1EnglishwhereWhile on the contrary; although; whereas; At or...
2Middle Englishwherwhere
3Old Englishhwǣrwhere
4Old English-aEnding forming adverbs; nominative masculine...
5Proto-GermanicCreates feminine nouns from roots and stems
6Proto-Germanic-ly; Forms agent nouns, often from the zero-grade...
7Proto-Indo-EuropeanDerives nouns from roots
Every word from Proto-Indo-European h₂en-