whereby

American  

[wair-bahy, hwair-] / wɛərˈbaɪ, ʰwɛər- /

conjunction

1. by what or by which; under the terms of which.

2. Obsolete. by what? how?

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whereby British  

/ wɛəˈbaɪ /

pronoun

1. by or because of which

   the means whereby he took his life

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adverb

1. archaic how? by what means?

   whereby does he recognize me?

Etymology

Origin of whereby

First recorded in 1150–1200, whereby is from the Middle English word wherby. See where, by

Example Sentences

"We all know the analogy whereby forests are the green lungs of the Earth," says Barthel.

From Science Daily • Feb. 24, 2026

Governing body the FIA has proposed a compromise whereby the ratio is measured both at ambient temperature and 130C.

From BBC • Feb. 20, 2026

Western Digital will conduct a debt-for-equity exchange whereby, before the offering is complete, it exchanges shares for some debt held by J.P.

From Barron's • Feb. 18, 2026

The problem for risk assets at present is strength in the yen is forcing an unwind of the carry-trade whereby traders borrow low-yielding Japanese money to reinvest in higher-yielding risk-on assets in global markets.

From MarketWatch • Feb. 13, 2026

In almost all other matters of Belief, of Opinion, or of Science; the assurance, whereby men are guided, is nothing near so firm, as this.

From "The Invention of Science" by David Wootton