1
: the way in which someone conducts oneself or behaves (see behave sense 1)
We were grateful for the gracious behavior of our hostess. The children were rewarded for good behavior. Be on your best behavior.
also : an instance of such behavior
unacceptable social behaviors
2
b
: anything that an organism does involving action and response to stimulation
c
: the response of an individual, group, or species to its environment
They are studying the behavior of elephants in the wild.
3
: the way in which something functions or operates
They tested the behavior of various metals under heat and pressure.
I'm surprised by her bad behavior toward her friends. Students will be rewarded for good behavior. scientists studying the behavior of elephants An acceptable social behavior in one country may be unacceptable in another country. Doctors are trying to educate people about behaviors that can put them at increased risk for skin cancer. The experiment tested the behavior of various metals under heat and pressure.
Recent Examples on the Web
Examples are automatically compiled from online sources to show current usage. Read More Opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback.
This confidence was hard-won over decades, yet it is being squandered through recent reckless fiscal behavior. —Les Rubin, Boston Herald, 25 Feb. 2026 This kind of grooming behavior was experienced by scores of girls and young women, many of whom reported it to the authorities. —Amy Wallace, Mercury News, 25 Feb. 2026 Though Soulwax’s night didn’t go off without a hitch — the event ended 15 minutes earlier than planned due to a noise complaint, and one attendee was removed for rowdy behavior — the Dewaele brothers are hopeful. —Ellise Shafer, Variety, 24 Feb. 2026 Reports of antisemitism Islamophobic behavior have increased markedly in Australia since the Israel-Hamas war began in 2023. —ABC News, 24 Feb. 2026 See All Example Sentences for behavior
Etymology
alteration of Middle English behavour, from behaven "to behave" + -our -or entry 2
First Known Use
15th century, in the meaning defined at sense 1
Time Traveler
The first known use of behavior was in the 15th century
“Behavior.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/behavior. Accessed 3 Mar. 2026.
Last Updated: - Updated example sentences
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