A star (in many cases a cataclysmic variable) that exhibits spectral lines at highly contrasting temperatures, such as those typical of a late-type red giant or supergiant (3000 K), and a dwarf B star (20 000 K). Such characteristics indicate that the star is an interacting binary. The group is very heterogeneous, but includes the relatively well-defined Z Andromedae stars, the symbiotic novae or RR Telescopii stars, and objects such as R Aquarii that appear to have an accretion disk and jets emerging approximately perpendicular to the plane of the disk. Mass transfer occurs either through mass streaming or as a stellar wind from the giant secondary.