There are a number of things which the term "ranking" might refer to.
Order of finishEdit
One meaning, also known as an order of finish, is "an ordering of the candidates from best to last according to societal preference". This type of ranking can be found with most voting methods. For voting methods that only give a winner and not a ranking, a ranking can be artificially created by putting the winner (winners, if there are multiple candidates who are tied) in 1st place, then removing them from all ballots, and finding a new winner who is in 2nd place, etc.
It is customary to refer to the worst candidate in a voting method's order of finish as the voting method's loser, even though technically all candidates who didn't finish in 1st place lost. For example, the Condorcet loser is the lowest-ranked candidate in the Condorcet ranking.