heliocentric parallax: the parallax of a celestial body using two points in the earth's orbit around the sun as the baseline
parallax: the apparent displacement of an object as seen from two different points that are not on a line with the object
china clay: a fine usually white clay formed by the weathering of aluminous minerals (as feldspar); used in ceramics and as an absorbent and as a filler (e.g., in paper)