activity

American  

[ak-tiv-i-tee] / ækˈtɪv ɪ ti /

noun

activities plural

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

But job growth -- often used as a proxy for economic activity -- has see-sawed wildly between expansion and contraction from month to month.

From Barron's • May 22, 2026

Zanjani—a former sheepskin trader who became one of Iran’s wealthiest men and most famous sanctions busters—ratcheted up activity on Binance through his crypto firm, Zedcex, in 2024, Binance compliance reports show.

From The Wall Street Journal • May 22, 2026

The second stage occurs later in life as normal genetic activity starts changing in ways that are no longer beneficial to the body.

From Science Daily • May 22, 2026

Automobile manufacturers and heavy industries are feeling the adverse affects of higher commodity prices, higher rates, slowing economic activity and increased uncertainty.

From MarketWatch • May 22, 2026

All three Marvellian cities have been on high alert for unusual activity and have enabled extra security precautions until she has been caught.

From "The Marvellers" by Dhonielle Clayton

Related Words

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