Principal English Translation: 

the name of a divine force or deity; curved obsidian blade

Attestations from sources in English: 

Also part of the compound name of a deity, Ixquimilli-Itztlacoliuhqui ("Eye Bundle-Curved Obsidian Blade), part of the Tetzcatlipoca complex, representing omnipotence, feasting and revelry
"Table 3. Major Deities of the Late Pre-Hispanic Central Mexican Nahua-Speaking Communities." Handbook of Middle American Indians, Volume 6: Social Anthropology, ed Manning Nash (Austin: University of Texas Press, 1967).

Ce Cuetzpalin, or One Lizard, a calendrical name and once another name for Itztlacoliuhqui; in the Treatise, it is an example of a tonalli that can be summoned (Atenango, between Mexico City and Acapulco, 1629)
Hernando Ruiz de Alarcón, Treatise on the Heathen Superstitions That Today Live Among the Indians Native to This New Spain, 1629, eds. and transl. J. Richard Andrews and Ross Hassig (Norman and London: University of Oklahoma Press, 1984), 220–221.

Also the name of the divine force relating to frost: "Cetl, mitoa: itztlacoliuhqui, cexiuhtica in oallatiuh, in ceuetzi: ipan ochpaniztli, in peoa ceuetzi. Auh chicoacempoalilhuitl, "[Frost]. The frost [god] was called Itztlacoliuhqui. Once yearly the cold came. During the feast of Ochpaniztli the cold began. And for one hundred and twenty days -- one hundred and twenty suns -- this persisted and there was cold. And it ended and disappeared [during the feast] called Tititl." (central Mexico, sixteenth century)
Fr. Bernardino de Sahagún, Florentine Codex: General History of the Things of New Spain; Book 7 -- The Sun, Moon, and Stars, and the Binding of the Venus, No. 14, Part VIII, 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, 1961), 19.