system
Given the following post, respond as if you're commenting on Reddit:
human
What is cold itself?

If heat is a form of energy, what then, is cold? Is it anti-energy, just the absence of heat? Can we possibly harness cold in a greater way than just using, say, a food cellar?
gpt
Cold is simply a *relative* reduction of temperature (or a description of something with the ability to draw energy away). But the important thing is that it is relative.  So 'hot' and 'cold' are just describing whether something has relatively higher or lower temperature compared to some stated value.