A warmblood is a middle-weight horse which was originally bred for riding, and in some cases pulling a carriage. Most warmblood lines originated in Europe and as their middling weight suggests that fall somewhere on the spectrum between a hotblooded racing horse and a coldblooded draft horse.
Warmbloods tend to be far more laid back than their hot-blooded counterparts, but are incredibly athletic and gymnastically capable. They are commonly the top choice of South African riders for dressage, showjumping and eventing, as these sports require not only good athletic ability, but also a cool-head.
Warmblood studs tend to put a lot of emphasis on performance, so are generally not afraid to cross with other breeds to breed favourable traits into these horses. Some stud registries actively encourage the inclusion of other breeds in warmblood lines to strive to improve the warmblood lines further.