n. A container designed to keep its contents at a constant humidity; especially such a box for storing cigars
The Century Dictionary and Cyclopedia
n. A box, often ornamental, in which cigars are kept moist or prevented from becoming too dry.
Word Usage
"The saloon-type room, designed by Italian designer Piero Lissoni, has comfortable sofas, a private balcony and an attached walk-in humidor, selling Cuban and Dominican cigars."