(mathematical analysis, of a function from a metric space X to a metric space Y) That for every real ε > 0 there exists a real δ > 0 such that for all pairs of points x and y in X for which D_X(x,y)<δ, it must be the case that D_Y(f(x),f(y))<ϵ (where D_X and D_Y are the metrics of X and Y, respectively).
In statistical hypothesis testing, a uniformly most powerful test is a hypothesis test which has the greatest power among all possible tests of a given size α.