Proper noun
Tlacopan
(historical) A Tepanec, Mexica altepetl on the western shore of Lake Texcoco.
During the Noche Triste (June 30 – July 1, 1520), the Spaniards managed a narrow escape from Tenochtitlan across the Tlacopan causeway, while their rearguard was being massacred. Source: Internet
There were three main streets that crossed the city, each leading to one of the three causeways to the mainland of Tepeyac, Ixtapalpa, and Tlacopan. Source: Internet