Wordnet 3.0
NOUN (1)
1. 
 a 6th century masterpiece of Byzantine architecture in Istanbul; 
 built as a Christian church, converted to a mosque in 1453, and made into a museum in the middle of the 20th century; 
[syn: Hagia Sophia, Hagia Sofia, Santa Sophia, Santa Sofia]
WordNet (r) 3.0 (2006):
Hagia Sophia
    n 1: a 6th century masterpiece of Byzantine architecture in
         Istanbul; built as a Christian church, converted to a
         mosque in 1453, and made into a museum in the middle of the
         20th century [syn: Hagia Sophia, Hagia Sofia, Santa
         Sophia, Santa Sofia]