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.
Uber and Consumer Reports also clashed over the investigation’s claim that 11% of discounts shown on the Uber app are based on inflated original prices, and therefore are not genuine discounts.
From Los Angeles Times • Jun. 16, 2026
Hradecky suggests the RAT was, therefore, more likely triggered because both engines had already lost power and fallen below idle speed, rather than by a separate electrical or hydraulic failure.
From BBC • Jun. 15, 2026
These indices instead base a stock’s index weight on fundamental criteria such as book value, revenue, cash flow, dividends and buybacks — therefore weighting stocks according to their economic significance rather than investor sentiment.
From MarketWatch • Jun. 15, 2026
“There’s a different set of people who I think are maybe thinking that ownership of this asset will be the only thing that matters in the future, and therefore they’re holding on to more.”
From The Wall Street Journal • Jun. 14, 2026
That didn’t seem to bother Bobby, since the shop opened late in the afternoon, and therefore it would be quiet in the mornings.
From "Endgame" by Frank Brady
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.
