Principal English Translation: 

the Eagle Door or Eagle Gate to the Templo Mayor patio (the location is a matter of some debate--see attestations); also cited as a neighborhood (barrio) of Tenochtitlan

Attestations from sources in English: 

"Cuauhquiyahuac was the correct designation of the south gate of the Tenochtitlan Templo Mayor enclosure..."
Le Mexique préhispanique et colonial: Hommage a Jaqueline de Durand-Forest (2004), 35.

Cuauhquiyahuac = Eagle doorway
John F. Schwaller, The Fifteenth Month (2019), 94.

"And it is called the Door of the Eagle, because an eagle was (standing) there engraved in stone...."
Thelma D. Sullivan's Compendium of Nahuatl Grammar (1988), 194.

"...Cuauhquiyahuac. On one side of the eagle was a tiger, also of stone, and on the other side a bear, also of stone. It is now clear that Sahagún's informants are describing the north side of the precinct...."
Eloise Quiñones Keber, Representing Aztec Ritual (2002), 49.

Attestations from sources in Spanish: 

"los españoles combatieron a los indios en el patio Cuauhquiyahuac"
Pilar Máynez, El Calepino de Sahagún (2014)).

Cuauhquiyahuac = un barrio indígena en la isla de Tenochtitlan
De márgenes, barrios y suburbios en la ciudad de México, coord. Marcela Dávalos (México: INAH, 2018).