behavior

American  

[bih-hayv-yer] / bɪˈheɪv jər /

especially British, behaviour

noun

• behaviors
  plural

1. 

   manner of behaving or acting.

   Synonyms:

   carriage, bearing, demeanor

2. Psychology, Animal Behavior.

   1. observable activity in a human or animal.

   2. the aggregate of responses to internal and external stimuli.

   3. a stereotyped, species-specific activity, as a courtship dance or startle reflex.

3. Often behaviors. a behavior pattern.

4. the action or reaction of any material under given circumstances.

   the behavior of tin under heat.

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behavior Scientific  

/ bĭ-hāv′yər /

1. The actions displayed by an organism in response to its environment.

2. One of these actions. Certain animal behaviors (such as nest building) result from instinct, while others (such as hunting) must be learned.

3. The manner in which a physical system, such as a gas, subatomic particle, or ecosystem, acts or functions, especially under specified conditions.

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behavior Idioms  

1. see on one's best behavior.

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Synonym Usage

Behavior, conduct, deportment, comportment refer to one's actions before or toward others, especially on a particular occasion. Behavior refers to actions usually measured by commonly accepted standards: His behavior at the party was childish. Conduct refers to actions viewed collectively, especially as measured by an ideal standard: Conduct is judged according to principles of ethics. Deportment is behavior related to a code or to an arbitrary standard: Deportment is guided by rules of etiquette. The teacher gave Susan a mark of B in deportment. Comportment is behavior as viewed from the standpoint of one's management of one's own actions: His comportment was marked by a quiet assurance.

Other Word Forms

Derived Forms

• interbehavior
  noun
• behavioral
  adjective

Inflected Forms

Nouns

• behaviors
  plural

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Etymology

Origin of behavior

First recorded in 1375–1425; behave ( def. ) + -ior (on model of havior, variant of havor, from Middle French (h)avoir “a having,” ultimately from Latin habēre “to have”); replacing late Middle English behavoure, behaver; see -or ¹ ( def. )

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Explanation

Behavior refers to how you conduct yourself. Generally, it’s wise to engage in good behavior, even if you're really bored. The noun behavior is a spin-off of the verb behave. Get rid of the be in behave and you're left with have, which makes sense: you could say that to behave is to "have" or "own" yourself — to control yourself. There's also a broader definition of behavior, which is basically anything any living thing does in any situation. Brushing your teeth? Behavior. Scratching your nose? Behavior. Eating a large antelope because you are a lion and you're hungry? Also behavior.

Example Sentences

See Examples For:

behavior behaviors

Can anyone truly be themselves when society’s bylaws not only dictate proper human behavior but also how successful anyone can be in something as complicated and unknowable as life itself?

From Salon ● Oct. 17, 2026

Although black holes are often portrayed as cosmic vacuum cleaners that swallow anything nearby, their feeding behavior is far more complicated.

From Science Daily ● Oct. 16, 2026

A top chipmaker’s chief executive likened some AI investors’ behavior to gambling.

From The Wall Street Journal ● Oct. 16, 2026

Neighbors noted the family of two was reserved and unsociable, but that their behavior was never alarming.

From Barron's ● Oct. 16, 2026

Volcanologists learned that past behavior of a volcano can only be treated as a bare minimum in hazard assessment.

From "Mountain of Fire" by Rebecca E. F. Barone

The story noted that the company flagged the potential for AI to display unpredictable and malicious behaviors as “risk factors.”

From MarketWatch ● Oct. 16, 2026

These behaviors often lead people to describe AI as though it can think, feel, or make decisions for itself.

From Science Daily ● Oct. 14, 2026

But he says "more than 30 years worth of behaviors" will need altering to make the railway run solely in the interests of the customer.

From BBC ● Oct. 12, 2026

Nearly 40 years later, NPCs have come a long way, with increasingly complex behaviors and conversational dialogue that span far more than just three words.

From Salon ● Oct. 12, 2026

Specific areas of the brain do control specific functions and behaviors, but it's not always as "logical" as we would imagine.

From "Phineas Gage" by John Fleischman

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Related Words

• act
• action
• attitude
• conduct
• demeanor
• management
• nature
• performance
• practice
• presence
• role
• style

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