The projective general linear group is the Group obtained from the General Linear Group on factoring the scalar Matrices contained in that group.
See also General Linear Group, Projective General Orthogonal Group, Projective General Unitary Group
Conway, J. H.; Curtis, R. T.; Norton, S. P.; Parker, R. A.; and Wilson, R. A.
``The Groups , ,
.'' §2.1 in
Atlas of Finite Groups: Maximal Subgroups and Ordinary Characters for Simple Groups. Oxford, England:
Clarendon Press, p. x, 1985.