activity

American  

[ak-tiv-i-tee] / ækˈtɪv ɪ ti /

noun

plural

activities

1. the state or quality of being active.

   There was not much activity in the stock market today. He doesn't have enough physical activity in his life.

2. a specific deed, action, function, or sphere of action.

   social activities.

3. work, especially in elementary grades at school, that involves direct experience by the student rather than textbook study.

4. energetic activity; animation; liveliness.

5. a use of energy or force; an active movement or operation.

6. normal mental or bodily power, function, or process.

7. Physical Chemistry. the capacity of a substance to react, corrected for the loss of reactivity due to the interaction of its constituents.

8. Physics.

   1. the number of atoms of a radioactive substance that disintegrate per unit of time, usually expressed in curies.

   2. radioactivity.

9. an organizational unit or the function it performs.

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activity British  

/ ækˈtɪvɪtɪ /

noun

1. the state or quality of being active

2. lively action or movement

3. any specific deed, action, pursuit, etc

   recreational activities

4. the number of disintegrations of a radioactive substance in a given unit of time, usually expressed in curies or disintegrations per second

5. 1. the capacity of a substance to undergo chemical change

   2. the effective concentration of a substance in a chemical system. The absolute activity of a substance B, λ B , is defined as exp (μ B RT ) where μ B is the chemical potential

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Other Word Forms

• nonactivity noun
• preactivity noun
• superactivity noun

Etymology

Origin of activity

First recorded in 1520–30; from Middle French or directly from Medieval Latin āctīvitās; see active, -ity

Explanation

An activity is something you do, or just the state of doing. You might plan some indoor activities for a rainy day, or you might just rely on watching your gerbils' activity in their cage. Usually, when you use an article like an or the in front of activity, you are referring to a specific event. For example, you might search for the best activity on the cruise ship to fill your afternoon — shuffleboard, anyone? If you take the article away, and you refer to activity, you are usually referring to action. If there is too much activity on the cruise ship dance floor, you might want to avoid that zone.

Example Sentences

It’s not just the physical hindrances that restrict commercial shipping activity.

From MarketWatch • Apr. 21, 2026

“Preventing activity lest it give rise to tax evasion places no limit whatsoever on Congress’s power under the taxation clause,” Judge Edith Jones writes for the unanimous panel in McNutt v.

From The Wall Street Journal • Apr. 20, 2026

This activity is believed to be aimed at shaping the data used to train future AI systems, potentially influencing how those systems behave and what information they prioritize.

From Science Daily • Apr. 20, 2026

Its leader Musa Seka Baluku reportedly first pledged allegiance to IS in 2016, but it was not until April 2019 that IS first acknowledged its activity in the area.

From BBC • Apr. 20, 2026

I nod along as Connor explains every single activity, every single trip and fall.

From "The Sea in Winter" by Christine Day

Related Words

• act
• endeavor
• enterprise
• job
• project
• scheme
• task
• venture
• work