for ‧ tress /ˈfɔːtrəs, ˈfɔːtrɪs $ ˈfɔːr-/ BrE AmE noun [countable]
[ Date: 1300-1400 ; Language: Old French ; Origin: forteresse 'strong place' , from Latin fortis 'strong' ]
a large strong building used for defending an important place
for ‧ tress /ˈfɔːtrəs, ˈfɔːtrɪs $ ˈfɔːr-/ BrE AmE noun [countable]
[ Date: 1300-1400 ; Language: Old French ; Origin: forteresse 'strong place' , from Latin fortis 'strong' ]
a large strong building used for defending an important place
Longman Dictionary of Contemporary English. Longman - Словарь современного английского языка. 2012