Essential or decisive for determining the outcome or future of something; extremely important; vital.
Very good; excellent; particularly applied to reggae music.
capable of being decided.
in intuitionistic logic, a proposition P is decidable in a given theory if it can be proven from the theory that "either P or not P", i.e. in symbols: P∨¬P.
describing a set for which there exists an algorithm that will determine whether any element is or is not within the set in a finite amount of time.