Definitions
1.nounA bet in which the bettor must select the first three placegetters of a race in the order in which they finish.
2.nounThe attainment of three important achievements, qualities, etc.
3.noun(by extension) A set of three related things, often things that cause problems."2011, Beatriz Scaglia, The Trifecta of Evil and the Crisis of Faith: Devil, Satan, and Lucifer."
4.noun(US politics) The complete legislative and executive control of state government by one party: governorship, the upper house, and the lower house of state legislatures. The party that holds all three positions of power is said to have a trifecta.
5.noun(US politics) Control by one party of the federal government: the presidency and both houses of Congress.