Looks like it's been explained here. Wankel was the German inventor that concieved and made it. It's actually yhe Wankel Rotary Engine, but most call it just the rotary(with the assumption that people know about it). The most unique gas engine in any production car. Mazda holds the license to it, though other companies tried thier own variations in the 60's/70s and failed. The rotary nearly put Mazda out of buisness in the mid '70s with the Oil Crisis, since the cars out then(the RX-2, RX-3, RX-4, RX-5 Cosmo, and REPU) got milage as low as 9mpg. With the RX-7 came new engineering and increased milage as well as increased reliability.
There has been a rotary Mazda sold every yearsince 1967 with the exception of mid 1992 before the 3rd gen RX-7 came out.
Hope that helps.