Tawny is a blend of ports, wood-aged in barrels for many years. It has a brownish, tawny colour — thus, its name.
Before Tawnies are bottled, they are “revived” with the addition of some younger port. The age on a bottle of Tawny — 10 years, 20 years, etc — is the average age of the blend.
Tawnies have a drier taste than other ports.