Dark rum is a black, brown, or reddish colored rum that has been aged and/or colored. If you shine a light on the bottle very little or no light will show through to the other side. This full-bodied style of rum became popular on English islands in the West Indies such as Jamaica and Bermuda as opposed to the lighter rums on Spanish islands such as Puerto Rico and Cuba.
The dark color can be achieved through caramel coloring and aging in new, used, or charred oak barrels. Also some of the molasses color and flavor is retained after distillation if the producer is distilling to a lower than normal proof.
You will find dark rum specified in a plethora of drink recipes from classic Tiki to boat drinks to cocktails. Dark rum is also used in cooking marinades, cakes, and other dishes.
The most common dark rum in the U.S. is Myers. This Jamaican dark rum is the template for most other dark rums. If a bar has a dark rum, chances are it will be Myers. You will also find Coruba (Jamaica), and Goslings dark rum (Black Seal from Bermuda).
These rums are nearly black in color and very full bodied. This type of rum is a staple and will be one of the mainstays of your bar. I keep Goslings dark rum on hand at all times.
Moving up a little lighter in color (but not much) are the dark brown or reddish rums. These include Ron Pampero Aniversario and aged Demerara rums such as El Dorado 12 Year. These rums have aromas and flavors of leather, spice, tobacco, and smoke and can be considered dark rums.
Once you get to a dark or medium amber in color you have aged rums (as I call them on this site).
Do you use a dark rum other than the big three I listed above? Let us know if you do.