[ ak-tiv-i-tee ]
/ ækˈtɪv ɪ ti /

noun, plural ac·tiv·i·ties.


Can You Ace This Quiz About “Compliment” vs. “Complement”?
Take this quiz to see if you really know the difference between “compliment” and “complement"!
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“Compliment” and “complement” had a shared meaning a long time ago, but today they are no longer interchangeable.

Origin of activity

1520–30; (< Middle French) < Medieval Latin āctīvitās. See active, -ity


non·ac·tiv·i·ty, noun, plural non·ac·tiv·i·ties.pre·ac·tiv·i·ty, noun, plural pre·ac·tiv·i··per·ac·tiv·i·ty, noun, plural su·per·ac·tiv·i·ties. Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2020

Example sentences from the Web for activities

British Dictionary definitions for activities

/ (ækˈtɪvɪtɪ) /

noun plural -ties

the state or quality of being active
lively action or movement
any specific deed, action, pursuit, etcrecreational activities
the number of disintegrations of a radioactive substance in a given unit of time, usually expressed in curies or disintegrations per second
  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
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

Medical definitions for activities

[ ăk-tĭvĭ-tē ]


A physiological process.
The presence of neurogenic electrical energy in electroencephalography.
An ideal concentration for which the law of mass action will apply perfectly.
The intensity of a radioactive source.
The ability to take part in a chemical reaction.
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.