A substance you can apply to wood to change its color, protect the wood, and give it a richer appearance. Stains come in oil-based and water-based varieties; the oil-based stains are reputed to have a richer color and perhaps offer more protection to the wood, but are less environmentally friendly. The water-based ones are easier to clean up and dispose of.

You can save a lot of money by buying unfinished furniture and staining it yourself, if you're willing to invest the sweat.