First-past-the-post (abbreviated FPTP or FPP) voting refers to an election won by the candidate(s) with the most votes. The winning candidate does not necessarily receive a majority of all votes cast. There is no ‘post’ (proportion of votes) that must be passed. [wikipedia]
Instant-runoff voting (IRV), also known as the alternative vote (AV), is a voting system used to elect one winner from a pool of candidates using preferential voting. Voters rank candidates in order of preference, and their votes are initially allocated to their first choice candidate. If after this initial count no candidate has a majority of votes cast, the candidate with the fewest votes is eliminated and votes for that candidate are redistributed according to the voters’ second preferences. This process continues until one candidate receives more than 50% of the votes, upon which they are declared the winner. [wikipedia]

