Principal English Translation:
a place in the middle of the lake, near Mexico Tenochtitlan; also described as being in a gulf of the lake
Fr. Bernardino de Sahagún, Florentine Codex: General History of the Things of New Spain; Book 2 -- The Ceremonies, No. 14, Part III, eds. and transl. Arthur J. O. Anderson and Charles E. Dibble (Santa Fe and Salt Lake City: School of American Research and the University of Utah, 1951), 42, 43.
Attestations from sources in English:
onnextlaoaloia, in tepetzinco, anoço vmpa in vel aytic, ytocaiocan pantitla: vmpa concaoaia in teteujtl = Blood sacrifices were made at Tepetzinco, or there in the very gulf of the lake at a place called Pantitlan. At this place they left consecrated papers (sixteenth century, central Mexico)
Fr. Bernardino de Sahagún, Florentine Codex: General History of the Things of New Spain; Book 2 -- The Ceremonies, No. 14, Part III, eds. and transl. Arthur J. O. Anderson and Charles E. Dibble (Santa Fe and Salt Lake City: School of American Research and the University of Utah, 1951), 42.