An Algol type star system is an eclipsing spectroscopic binary consisting of two close, interacting stars. Their X-ray emission is due to slow mass transfer due to Roche lobe overflow. Algol-type systems named after the first discovery of this type, the Algol system, researched by various astronomers from 1667 until Pickering and Vogel nailed what it was in 1889

However, later observations could have disqualified Algol from being an Algol-type system, since it's actually a triple star system (a trenary). However, saying that Algol is not an Algol-type system is just too silly. What's next, claiming Pluto isn't a planet?