A compass points toward the north magnetic pole; that means the N pole of the compass is attracted to the north magnetic pole. Unlike poles attract, and so the north magnetic pole is an S pole. Compare the Earth's magnetic field (with all the field lines pointing north, the way a compass would point) with the field of a bar magnet.
This is why physicists like to call them N and S poles instead of North and South poles: it's less confusing to say "the north magnetic pole is an S pole" than "the north magnetic pole is a south pole."