Añejo tequilas have been aged a minimum of one year, typically in used bourbon barrels from right here in the States, just like how scotch does it.
As of 2006, this new designation is reserved for tequilas aged a minimum of three years in oak barrels.
What you’ve probably been drinking most of your life, Blancos are no more than 60 days old and have little to no coloring.
Sometimes called “gold”, Jovens are typically blanco mixtos that have had coloring and flavoring added.
Normas Oficial Mexicana (NOM)
Similar to France's appellation d'origine contrôlée, the NOM dudes stamp bottles, certifying that the hooch in question meets the geographic- and ingredient-based requirements of Tequila. The stamp doesn’t mean the booze is good, but it does mean it's authentic.