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.
"That secondary dip tells us how bright, and therefore how hot, the planet is," said Wilson.
From Science Daily • Jun. 1, 2026
The case therefore demands a closer look at both compassionate release and federal habeas corpus.
From Slate • May 29, 2026
The deepest danger is that we come to see ourselves as machines and therefore accept being governed as machines.
From The Wall Street Journal • May 28, 2026
And that means 24 knockout ties in round two - which must therefore have 48 teams.
From BBC • May 28, 2026
I didn’t have much time to examine the nest last night, but do think it is possible that the adults were the former habitants of the nest and, therefore, the eaglet’s parents.
From "A Bird Will Soar" by Alison Green Myers
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.
