* Volcanic cone: This is the most common meaning. In geology, a puy refers to a small volcanic cone, especially in the region of the Auvergne in France. It's often used specifically for the volcanic cones of the Massif Central.
* Hill: In a broader sense, puy can also simply mean hill or mound, even if it's not of volcanic origin.
So, the best translation of "puy" depends on the specific context. If you're talking about a geographical feature in the Auvergne, it almost certainly refers to a volcanic cone. If you're talking about a hill in a different part of France, it could refer to a more general hill.