Wiktionary
n. (cx crystallography mineralogy English) The set of all symmetry operations that can be applied to a given crystal without changing it.
Wikipedia
In mathematics, physics and chemistry, a space group is the symmetry group of a configuration in space, usually in three dimensions. In three dimensions, there are 219 distinct types, or 230 if chiral copies are considered distinct. Space groups are also studied in dimensions other than 3 where they are sometimes called Bieberbach groups, and are discrete cocompact groups of isometries of an oriented Euclidean space.
In crystallography, space groups are also called the crystallographic or Fedorov groups, and represent a description of the symmetry of the crystal. A definitive source regarding 3-dimensional space groups is the International Tables for Crystallography .
Usage examples of "space group".
Soviets had included the last location because they knew that Norman Grant, a major force in aviation and space groups in the Senate, lived there.