In terms of the
US presidential election system, it is how many people all across the country voted someone, as opposed to how many
electoral votes the
candidate got.
Popular vote doesn't actually matter, as we can see in the
recent election. The winner of the popular vote in a state gets the
electoral votes for that state. Therefore, it is possible for a candidate to win the
presidential election without having the popular vote in the
country.
Also, popular vote for election is
never known since
not all votes are counted. When a candidate gets the votes of 51% of a state's
registered voters, the rest of the
ballots can be ignored. Therefore, you can't say that
Al Gore won the popular vote, since he only "won" it by about
300, 000 and in just
California more than that many
votes were ignored.