fortress

Origin

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.