a system of voting, as in some corporate and legislative elections, in which each voter is allowed as many votes as there are offices to be filled and may freely allocate them among the candidates, even by giving all the votes to one candidate
See cumulative voting in American Heritage Dictionary 4
cumulative voting
noun
A system of voting in which each voter is given as many votes as there are positions to be filled and allowed to cast those votes for one candidate or distribute them in any way among the candidates.