What's a "humidor"?

Mine's been empty for years, have cut way back on smoking cigars, but a few here and there and smoke them immediately. 30% employee discount since the wine store sells Padrons (yes, the 64s and the 26s). Been smoking the 64 Exclusivo Maduros for quite some time now BUT we're having a hard time getting them so maybe BadWhales and I will have to do a split.