[ ak-tiv-i-tee ]
See synonyms for: activityactivities on

noun,plural ac·tiv·i·ties.
  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.

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

  2. energetic activity; animation; liveliness.

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

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

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

  6. Physics.

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

  7. an organizational unit or the function it performs.

Origin of activity

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

Other words from activity

  • non·ac·tiv·i·ty, noun, plural non·ac·tiv·i·ties.
  • pre·ac·tiv·i·ty, noun, plural pre·ac·tiv·i·ties.
  • su·per·ac·tiv·i·ty, noun, plural su·per·ac·tiv·i·ties.

Words Nearby activity Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2023

How to use activity in a sentence

British Dictionary definitions for activity


/ (ækˈtɪvɪtɪ) /

nounplural -ties
  1. the state or quality of being active

  2. lively action or movement

  1. any specific deed, action, pursuit, etc: recreational activities

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

    • the capacity of a substance to undergo chemical change

    • 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

Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012