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

• behavioral
  adjective
• interbehavior
  noun

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

The V-shaped trading pattern of the last 24 hrs reflects in part the behavior of the Philadelphia Semiconductor Index SOX, the broad movements of which Korea’s market has been tracking for some time.

From MarketWatch • Jun. 9, 2026

Whether you're navigating a job interview, meeting someone for the first time, or responding to an unexpected challenge, success often depends on your ability to adjust your behavior.

From Science Daily • Jun. 8, 2026

They lead storytime, serve breakfast on plastic plates and in sippy cups, lead music and movement activities, and handle tears and rambunctious behavior.

From Los Angeles Times • Jun. 8, 2026

Like the backrooms, one can find faithful representations of human behavior, and unfaithful representations.

From Salon • Jun. 8, 2026

Despite my attempt to be nonchalant, I knew my behavior wasn’t going unnoticed.

From "The Red Car to Hollywood" by Jennie Liu

Related Words

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