hypothesis

American  

[hahy-poth-uh-sis, hi-] / haɪˈpɒθ ə sɪs, hɪ- /

noun

hypotheses plural

1. 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.

2. a proposition assumed as a premise in an argument.

3. the antecedent of a conditional proposition.

4. a mere assumption or guess.

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hypothesis British  

/ haɪˈpɒθɪsɪs /

noun

1. 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

2. an assumption used in an argument without its being endorsed; a supposition

3. an unproved theory; a conjecture

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hypothesis Scientific  

/ hī-pŏth′ĭ-sĭs /

hypotheses plural

1. A statement that explains or makes generalizations about a set of facts or principles, usually forming a basis for possible experiments to confirm its viability.

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hypothesis Cultural  

1. plur. hypotheses (heye-poth-uh-seez) In science, a statement of a possible explanation for some natural phenomenon. A hypothesis is tested by drawing conclusions from it; if observation and experimentation show a conclusion to be false, the hypothesis must be false. (See scientific method and theory.)

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Usage

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.

Synonym Usage

See theory.

Other Word Forms

Derived Forms

• counterhypothesis
  noun
• hypothesist
  noun
• subhypothesis
  noun

Inflected Forms

Nouns

• hypotheses
  plural

Etymology

Origin of hypothesis

First recorded in 1590–1600, hypothesis is from the Greek word hypóthesis “basis, supposition”; see hypo-, thesis

Explanation

In science, a hypothesis is an idea or explanation that you then test through study and experimentation. Outside science, a theory or guess can also be called a hypothesis. A hypothesis is something more than a wild guess but less than a well-established theory. In science, a hypothesis needs to go through a lot of testing before it gets labeled a theory. In the non-scientific world, the word is used a lot more loosely. A detective might have a hypothesis about a crime, and a mother might have a hypothesis about who spilled juice on the rug. Anyone who uses the word hypothesis is making a guess.

Example Sentences

See Examples For:

hypothesis hypotheses

If the hypothesis is correct, it could expand scientists' understanding of how volcanoes form and encourage researchers to look for similar geological processes elsewhere in the world.

From Science Daily ● Jul. 10, 2026

The efficient-markets hypothesis, developed decades ago by economists at the University of Chicago, stipulates that all available information is already factored into the market price.

From MarketWatch ● Jun. 25, 2026

A nice historical example of the good kind of hard problem centers on Bernhard Riemann—but work far removed from prime numbers and the hypothesis that bears his name.

From Slate ● Jun. 22, 2026

According to this hypothesis, the systems briefly misidentified the aircraft as being on the ground, prompting a protection system to interpret high engine thrust as a malfunction and cut fuel to both engines.

From BBC ● Jun. 15, 2026

Boveri’s hypothesis was corroborated by work performed by two other scientists.

From "The Gene" by Siddhartha Mukherjee

The continuing delay, he argues, points to competing hypotheses, unresolved leads and possible mechanical issues that have yet to be fully explained.

From BBC ● Jun. 15, 2026

It also puts forward hypotheses about why this belly-brain choreography exists.

From Los Angeles Times ● May 7, 2026

As he had done at Renault, de Meo distilled his hypotheses into a short memo, circulated to senior managers on his first day.

From The Wall Street Journal ● Apr. 9, 2026

In total, the team evaluated more than 700 hypotheses and asked the same question 10 times for each one to measure consistency.

From Science Daily ● Mar. 17, 2026

One of our hypotheses seemed to be confirmed a few months later when we were joined by Kathy, who had indeed been a member of the High Organ.

From "Long Walk to Freedom" by Nelson Mandela

Related Words

• assumption
• axiom
• conclusion
• conjecture
• explanation
• guess
• inference
• interpretation
• premise
• proposition
• rationale
• supposition
• theorem
• thesis