Noun

(en noun)

An action or statement in response to a stimulus or other event

The announcement of the verdict brought a violent reaction .

You were in the courtroom. What is your reaction ?

When I last tried to eat strawberries I had a terrible allergic reaction .

(chemistry) A transformation in which one or more substances is converted into another by combination or decomposition

In this reaction , the acid and base will neutralize each other, producing a salt.

Noun

(activities)

The state or quality of being active; nimbleness; agility; vigorous action or operation; energy; active force; as, an increasing variety of human activities.

Something done as an action or a movement.

Something done for pleasure or entertainment, especially one involving movement or an excursion.

* {{quote-magazine, date=2013-06-07, author=David Simpson

, volume=188, issue=26, page=36, magazine=(The Guardian Weekly) , title= Fantasy of navigation , passage=Like most human activities , ballooning has sponsored heroes and hucksters and a good deal in between. For every dedicated scientist patiently recording atmospheric pressure and wind speed while shivering at high altitudes, there is a carnival barker with a bevy of pretty girls willing to dangle from a basket or parachute down to earth.}}

Use (of internet, playstation, bank account etc.).