what is a complex hybrid

Hello,
Could anybody please tell me - when hybrid becomes complex?
As I understood cross between two species is a primary hybrid, for example:
hangianum x vietnamense = Paph. Annie Fuchs
Is anything that not primary - complex or is it more complicated then that? What are other hybrid types?
Also what type of hybrid would be between a specie and hybrid, for example:
Paph. Carolyn Butcher (delenatii x Fanaticum)

Thanks a lot.