As an auxiliary, used to express completed action: originally causal after have or had, followed by an object infinitive; in present use the have or had is often omitted and the infinitive turned into a preterit, leaving done as a mere preterit sign.Completed; finished; decided; accepted: used in an exclamatory way to signify acceptance of a proposition, as a wager.Completely used up; thoroughly fatigued; tired out: sometimes with out or up (or with for: see to do for, under do, verb).Completed; executed; issued; made public: used chiefly in the concluding clause of a formal document, expressing the place at which and the date on which it received official sanction and became valid: as, done at Washington this 15th day of May, etc.An obsolete form of the infinitive (and present indicative plural) of do.