hypothesis
Americannoun
plural
hypotheses-
a proposition, or set of propositions, set forth as an explanation for the occurrence of some specified group of phenomena, either asserted merely as a provisional conjecture to guide investigation working hypothesis or accepted as highly probable in the light of established facts.
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a proposition assumed as a premise in an argument.
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the antecedent of a conditional proposition.
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a mere assumption or guess.
noun
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a suggested explanation for a group of facts or phenomena, either accepted as a basis for further verification ( working hypothesis ) or accepted as likely to be true Compare theory
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an assumption used in an argument without its being endorsed; a supposition
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an unproved theory; a conjecture
plural
hypothesesUsage
What is a hypothesis? In science, a hypothesis is a statement or proposition that attempts to explain phenomena or facts. Hypotheses are often tested to see if they are accurate.Crafting a useful hypothesis is one of the early steps in the scientific method, which is central to every field of scientific experimentation. A useful scientific hypothesis is based on current, accepted scientific knowledge and is testable.Outside of science, the word hypothesis is often used more loosely to mean a guess or prediction.
Related Words
See theory.
Other Word Forms
- counterhypothesis noun
- hypothesist noun
- subhypothesis noun
Etymology
Origin of hypothesis
First recorded in 1590–1600, hypothesis is from the Greek word hypóthesis “basis, supposition”; hypo-, thesis
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.
Subject lines include “Recognizing the need for fasting,” “Mice blood age affects Alzheimer’s brain changes,” and “A casual hypothesis about epigenetics.”
From Slate • Mar. 30, 2026
The biggest flaw in the Hegelian viewpoint about supposedly great men is that his entire hypothesis about an unfolding historical process is flat wrong.
From Salon • Mar. 28, 2026
"We were exceptionally lucky to find these -- a real 'needle-in-a-haystack' effort. These prove the impact crater hypothesis beyond doubt, because they have a fabric that can only be created by extreme shock pressures."
From Science Daily • Mar. 11, 2026
The hypothesis is that the submarine suffered a valve failure that allowed water to enter the battery compartment, triggering a fire and then an explosion.
From Barron's • Mar. 3, 2026
"Now, if you done interrupting, let me continue with my hypothesis."
From "Look Both Ways" by Jason Reynolds
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.
