Noun
Coxeter group (plural Coxeter groups)
(mathematics, geometry, group theory) Any of a class of groups whose finite cases are precisely the finite reflection groups (including the symmetry groups of polytopes), but which are more varied in their infinite cases, and whose range of application encompasses various areas of mathematics.
Compact Euclidean uniform tessellations (by their infinite Coxeter group families) Fundamental domains in a cubic element of three groups. Source: Internet