Definition
In the context of magnetism, the south pole is one of the two ends of a magnet, where magnetic field lines enter the magnet. In Earth's magnetic field, the magnetic south pole is the point in the southern hemisphere where the planet's magnetic field lines emerge vertically. Note that Earth's geographic South Pole and its magnetic south pole are not in the same location, and the two are offset by hundreds of miles.
Plain English
One end of a magnet, or the corresponding region near the bottom of the Earth where the planet acts like a giant magnet. The Earth's magnetic south pole is not in the exact same place as the geographic South Pole at the bottom of the globe.
Context Anchor
Seen in magnetic compass discussions when explaining why a compass needle lines up in a particular direction.
Derivation
From Latin polus, meaning 'end of an axis.' In magnetism, the term was borrowed from astronomy and geography because a magnet has two opposite ends, mirroring how the Earth has two opposite ends of its rotational axis.
Why Pilots Care
The compass works because a magnetized needle aligns with Earth's magnetic field, which runs between the magnetic north and south poles. Because these magnetic poles do not match the geographic poles, the compass does not point to true north — it points to magnetic north, which is why pilots must apply variation when navigating.
Grounding Statement
Picture a simple bar magnet marked N on one end and S on the other; the S end is the south pole.
Intuition Check
South pole does not mean the geographic South Pole on a map here. In this compass context, it means the south end of a magnet.
Example Sentence 1
The compass needle aligns itself with the line between the Earth's magnetic north and south poles.
Example Sentence 2
Understanding the location of the magnetic south pole helps explain why the compass works at all latitudes.