A fortress is a large building or complex of buildings used as a military stronghold. In a military sense, a fortress is often called a “fort."

From its original sense of stronghold, the word fortress has stretched to include strongholds in a more figurative sense. Martin Luther used fortress to describe unfailing spiritual support when he wrote, “A mighty fortress is our God.” When someone has a hard time trusting others, you might say they have retreated to a "fortress of their own making."

Definitions of fortress

n a fortified defensive structure

show 4 examples...
hide 4 examples...
a fortified Moorish palace built near Granada by Muslim kings in the Middle Ages
a fortress built in Paris in the 14th century and used as a prison in the 17th and 18th centuries; it was destroyed July 14, 1789 at the start of the French Revolution
Tower of London
a fortress in London on the Thames; used as a palace and a state prison and now as a museum containing the crown jewels
Machu Picchu
Inca fortress city in the Andes in Peru discovered in 1911; it may have been built in the 15th century
show 4 types...
hide 4 types...
any of various Spanish fortresses or palaces built by the Moors
martello tower
a circular masonry fort for coastal defence
a fortress established in the southwestern United States by the Spanish in order to protect their missions and other holdings
a small fort or earthwork defending a ford, pass, or castle gate
Type of:
defence, defense, defensive structure
a structure used to defend against attack

Sign up, it's free!

Whether you're a student, an educator, or a lifelong learner, can put you on the path to systematic vocabulary improvement.