"Entheogen" does not literally mean "something that brings about a god within," it's more along the lines of "something that places you within god." From Greek en-theos, within god. A subtle but important difference, even if that interpretation does make the description less profound. It also does not (by its originally translated meaning at least) necessarily have anything to do with psychedelic drugs.

As I interpret it, an entheogen is anything that makes you feel as though you understand reality in the way a god might. Thus, many things are entheogens: learning, creating, art, sex, music, love, hate, science, drugs, reading, religion, dreaming, dancing, touching, power, and so forth.