. Majority, plurality, in the context of an election, poll, or other voting situation resulting in a statistically based statement, both denote an amount or number larger than some other. In situations in which only two candidates, options, or positions are concerned, the terms are interchangeable, though majority is by far the more commonly used:
http://www.dictionary.com/browse/majority?s=t
Hmm, let’s go ahead and post the whole paragraph from that link, shall we?
3. Majority, plurality, in the context of an election, poll, or other voting situation resulting in a statistically based statement, both denote an amount or number larger than some other. In situations in which only two candidates, options, or positions are concerned, the terms are interchangeable, though majority is by far the more commonly used: She beat her opponent by a large majority. The proposal received a large plurality of “Yes” votes. When three or more choices are available, however, a distinction is made between majority and plurality. A majority, then, consists of more than one-half of all the votes cast, while a plurality is merely the number of votes one candidate receives in excess of the votes for the candidate with the next largest number. Thus, in an election in which three candidates receive respectively 500, 300, and 200 votes, the first candidate has a plurality of 200 votes, but not a majority of all the votes cast. If the three candidates receive 600, 300, and 100 votes, the first has a majority of 100 votes (that is 100 votes more than one-half the total of 1000 cast) and a plurality of 300 votes over the nearest opponent.