Something done as an action or a movement.
The lexical aspect (aktionsart) of verbs or predicates that change over time and have no natural end point.
Something done for pleasure or entertainment, especially one involving movement or an excursion.
The state or quality of being active; activeness.
The number of radioactive decays per unit time. Unit for it: becquerel or curie
The propery of substances to react with other substances
The act of one who undertakes (in either sense).
A promise or pledge; a guarantee.
That which is undertaken; any business, work, or project which a person engages in, or attempts to perform; an enterprise.
The business of an undertaker, or the management of funerals.