AC in the context of electricity has meant "alternating current" for literally more than a hundred years. This is a you problem, not OP's, so turn down the snark. https://en.wikipedia.org/wiki/Alternating_current

AC, or alternating current, is a type of power. Usually available as a wall plug in your house.

DC, or direct current, is another type. For example a battery. Or in this case, PoE.

Your comment may inspire someone to make an air conditioner that runs on PoE...