CRIANZA is a general Spanish wine term relating to the maturation of a wine prior to its sale. But it also has a locally-defined meaning: in Rioja, for example, a red Crianza must legally spend at least one year in oak barrel (generally not new) plus a year in bottle.
In terms of style, Crianzas tend to be medium to full bodied, fairly rich and with approachable fruit and sweet spice flavours. The New York Times’ wine writer Eric Asimov says that “no other category of Spanish red wine is as consistently satisfying and as good value as Rioja crianza.”
Unlike ‘Reserva’ (which indicates a longer ageing period) the term ‘Crianza’ hasn’t been hijacked by New World producers. If you want to sound impressive, say Crianza like a true Castillian by using the ‘voiceless dental fricative‘ phoneme: basically, pronounce the ‘z’ as ‘th’. You won’t sound pretentious at all, honest ;)