The ancient Greeks used two words to denote time: chronos (χρόνος) and kairos (καιρός). Chronos is the word from which we get the term chronology. It defines time as a measurable resource or a sequential ordering of events. Kairos, however, implies a different category of time. It refers to an appointed time, an opportune moment, or a due season. Whereas chronos is quantitative, kairos is qualitative. In ancient Greek rhetoric, a kairos moment suggested possibility, an occasion for the wise to seize in order to achieve success. All time, then, is not equal, for not every second possesses the same worth.