therefore
Americanadverb
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thus; hence: used to mark an inference on the speaker's part
those people have their umbrellas up: therefore, it must be raining
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consequently; as a result
they heard the warning on the radio and therefore took another route
Synonym Usage
Therefore, wherefore, accordingly, consequently, so, then all introduce a statement resulting from, or caused by, what immediately precedes. Therefore (for this or that reason) and wherefore (for which reason) imply exactness of reasoning; they are especially used in logic, law, mathematics, etc., and in a formal style of speaking or writing. Accordingly (in conformity with the preceding) and consequently (as a result, or sequence, or effect of the preceding), although also somewhat formal, occur mainly in less technical contexts. So (because the preceding is true or this being the case) and then (since the preceding is true) are informal or conversational in tone.
Etymology
Origin of therefore
First recorded in 1125–75; Middle English ther(e)fore, variant of therfor therefor
Compare meaning
How does therefore compare to similar and commonly confused words? Explore the most common comparisons:
Explanation
The adverb therefore means as a result or consequence, or "for that reason." Cats and dogs tend to fight; therefore, keep your pets apart at night if you want to get some sleep. The adverb therefore is also used to introduce a conclusion that follows based on logic. You'll see this construction a lot in logic, math, and science, for example. Of course, sometimes the conclusions are false, as in this argument: "All fish live in water. A whale lives in water. Therefore, a whale is a fish." A whale is, in fact, a mammal. Therefore, the argument that a whale is a fish is wrong.
Example Sentences
Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.
"We therefore call on our industry peers, TikTok and YouTube, to implement this new framework, right away."
From Barron's ● Aug. 26, 2026
The pressure could therefore become much more serious if Washington manages to close channels that survived previous sanctions, particularly those involving China and Iran's neighbours.
From BBC ● Aug. 25, 2026
We’re also made acutely aware of what we’re not seeing, that no picture is the whole picture and there is narrative power in the denial of sight and therefore knowledge.
From Los Angeles Times ● Aug. 25, 2026
The indicator’s theoretical rationale is that households are late to jump on the market’s bandwagon, and are therefore most bullish at or near tops and most bearish at or near bottoms.
From MarketWatch ● Aug. 24, 2026
It says, therefore, a great deal in Christopher Forrester’s favor that he refused —with speed and cunning and courage—to be eaten.
From "Impossible Creatures" by Katherine Rundell
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Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023
Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.