fortress
n. countablen. a strong building or town that is protected against attacks. It usually has thick walls and is hard to enter.
n. a heavily fortified building or strategic position designed to withstand military assault. Often used metaphorically to describe a place or person that is very difficult to reach or influence.
The soldiers guarded the entrance to the fortress.
The ancient fortress sits high on a hill, giving the defenders a clear view of any approaching enemies.
While the castle served as a royal residence, the outer fortress was designed purely for defense, featuring thick stone ramparts and narrow slits for archers.
Early 14 c., from Old French forteresce, forteresse, forterece (“strong place, fortification”), variant of fortelesse, from Medieval Latin fortalitia, from Latin fortis (“strong”) (see fort) + -itia, added to adjectives to form nouns of quality or condition. French -ess, from Latin -itia is also in words such as duress, prowess, largesse and richesse. For change of medial -l- to -r- in Old French, compare orne (“elm”) from ulmus; chartre from cartula and chapitre from capitulum. First attested in the 12th century.
Often used with the preposition 'of' in metaphorical contexts, such as 'a fortress of solitude'.