Blended port, as opposed to a 'vintage' port.

Like Ruby Port, Tawny Port is a blended wine, but one that is aged for a minimum of four years in wood casks and is lighter. It is called "tawny" because as oxidation occurs, the original ruby-red color changes into a reddish brown.

A Port that has been aged in a barrel instead of a bottle. The process allows the wine to take on a nutty aroma, and to loose its red color over time (turning a tawny brown). The best examples are usually labeled in decades, such as a 10-year-old, 20-year-old or 40-year-old. Inexpensive tawny ports may be a blend of red and white port, and do not resemble the real thing in any way. The US and Australia make fortified wines that they continue to label "Port" and the tawny versions of some of these are a relative bargain.