There is not just one buddha in the world. Indeed there are very many and the various buddhas in the world take different forms and benefit beings in different ways. While there are buddhas in the various realms they are not of a very conspicuous nature. When we talk about the Buddha, or a person being a buddha, we are referring to someone whose compassion and wisdom have reached their highest potential. Every one of us has compassion and every one of us has wisdom. The difference between our compassion and wisdom and the Buddha’s, however, is that our compassion and wisdom have not reached such mighty and elevated levels.
Depicted from "Meditation and Tantra in Harmony - Part 3"