What does Crianza mean when talking about Spanish wines (specifically
in Marques de Caceres)?

Is it an area, a style of wine etc?

Should Marques de Caceres' "straight" Rioja be refered to as M de C
Rioja or M de C Rioja Crianza? Is one specifically incorrect, or is
it more a case that it should really be referred to as the one with
Crianza in the title, but people just tend to drop the Crianza part
for the sake of simplicity?

Richard