# activity

Pronunciation: say "ak-TIV-i-tee" US /ækˈtɪv.ɪ.ti/, UK /ækˈtɪv.ɪ.tiː/

## Noun

1. Something that a person or group does, especially for a particular purpose or for enjoyment.
   - Simple: Something you do, especially for work, learning, exercise, or fun.
   - _Stretching counts as a light physical activity that improves circulation._
   - _Each task on the schedule was listed as a separate activity._
2. The state or quality of being active; busy movement or motion.
   - Simple: The state of being busy and moving around a lot.
   - _Seismic activity increased in the days before the eruption._
   - _The trading floor buzzed with activity as the bell rang._
3. The tendency or power of a substance to react chemically with others.
   - Simple: How easily a substance reacts with other substances.
   - _Fluorine shows extremely high activity, reacting with nearly every element._
   - _Chemists compared the activity of each catalyst before the trial._
4. The number of radioactive decays that occur per unit of time, measured in becquerels or curies.
   - Simple: How many times a radioactive material breaks down each second.
   - _The activity of the cesium source was recorded in becquerels._
   - _As the isotope decayed, its activity dropped steadily over the month._

## Other meanings

- (noun) The lexical aspect of verbs or predicates that describe change over time but have no natural end point.

## Origin

The Latin noun activitas passed into Middle French as activité, and English took it from there. In English terms, it is simply active with the suffix -ity added.

Source: DictionaryAI, https://dictionaryai.com/define/activity (written from Wiktionary data, CC BY-SA 4.0: https://creativecommons.org/licenses/by-sa/4.0/).