The name Macau is derived from the Chinese A-ma-gao Bay of A-Ma. A-ma was the name of a Chinese goddess, popular with the Chinese seafarers and fishermen who had a temple on the peninsula when the Portuguese first anchored there in 1513. Macau’s culture name is Macanese, and its alternative names are Macao, Aomen, and Haijing Ao.

Source: http://www.everyculture.com/Ja-Ma/Macau.html