Having, considering, or based on, the earth as center; as, the geocentric theory of the universe; in relation to or seen from the earth, -- usually opposed to heliocentric, as seen from the sun; as, the geocentric longitude or latitude of a planet.
Viewed from the Earth, as if Earth were the center of the Universe. Since a person on Earth sees the Cosmos from an earthly perspective, the birth chart is drawn with that vantage point. We see the sky (and everything else) relative to ourselves- each of us is the center of our own personal Universe.
Sometimes called the Ptolemaic theory, it was commonly believed before Copernicus that the Earth was the center of the universe, and that the sun, moon, planets, and stars all revolved around the Earth.
Geocentric acts as though the planets revolve around the earth. Since we are on the earth, this seems like a reasonable way to figure out how the planets would affect us here. This is the form of astrology that we use.