classical group
groups representable as matrix groups over a real division associative algebra (reals, complexes, or quaternions) that preserve a certain bilinear form (symmetric, skew-symmetric, Hermitian, skew-Hermitian, etc.)
en-US/ˈklæsɪkəl ˈɡɹup/
en-GB/ˈklæsɪkl ˈɡɹuːp/