A pole is either of two opposite ends. For instance, Earth has a North and South Pole. These sit at opposite ends of Earth’s axis of rotation. Other celestial bodies, such as the moon and Jupiter, also have poles. Every magnet has a north and a south pole, too. These are the opposite ends of a magnet where its magnetic field is strongest.
The adjective “polar” describes things that are related to or have poles. For example, some molecules are polar molecules. These are molecules that have a positively charged pole on one side and a negatively charged pole on the other. Polar bears, meanwhile, get their name from living near Earth’s North Pole.