activity

Activity may mean:action, in generalActivity, an alternative name for the game charadesActivity, a task.Activity, the ability of a piece to influence the game in chessActivity, the rate of a catalytic reaction, such as enzyme activity, in physical chemistry and enzymologyactivity (chemistry), the effective concentration of a solute for the purposes of mass action activity (project management)activity (radioactivity), the number of disintegrations per secondactivity (software engineering)activity (soil mechanics)activity diagram, a diagram representing activities in UMLHMS Activity, an aircraft carrier of the Royal Navy
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(n.)
The state or quality of being active; nimbleness; agility; vigorous action or operation; energy; active force; as, an increasing variety of human activities.
  

noun
what something does; the drug's activity did not last more than a few hours
antibacterial activity = effective action against bacteria

(a) An effective thermodynamic concentration used in thermodynamic calculations in place of the actual concentration to allow equations developed for ideal solutions to be used to treat real solutions.