behavior

American  

[bih-heyv-yer] / bɪˈheɪv yər /

especially British, behaviour

noun

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.

---

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.

---

behavior Idioms  

1. see on one's best behavior.

---

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

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. )

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

"Everyone has seen a street musician or a performer adjust to a changing crowd," said Nieh, a faculty member in the Department of Ecology, Behavior and Evolution.

From Science Daily • Mar. 24, 2026

Meanwhile, the cover of “The Behavior Gap,” his 2012 bestseller, features a roller-coaster line showing the ups and downs of greed and fear.

From MarketWatch • Mar. 16, 2026

"Even small changes in their environment can make them suspicious," said Loretto, who is at the University of Veterinary Medicine in Vienna, and began the research at the Max Planck Institute of Animal Behavior.

From Barron's • Mar. 12, 2026

Behavior analysts at Action were paid bonuses for working more hours of “treatment delivery” services, starting at 30 hours per week, according to a document reviewed by the Journal.

From The Wall Street Journal • Mar. 11, 2026

The list was very long—so long, in fact, that the authors of Standards of Inmate Behavior found it easier to define what was permitted than what wasn’t.

From "Newjack: Guarding Sing Sing" by Ted Conover

Related Words

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