Aristotype

An arisotype in crystallography is a high-symmetry structure type that can be viewed as an idealized version of a lower symmetry structure. I believe Helen Megaw introduced the term in relation to perovskites which it is where it is still mostly used, the cubic perovskite structure (which is adopted at most half a dozen compounds) is regarded as the aristotype for the vast array of other lower-symmetry perovskites.