a thorn; a hairy worm; a caterpillar; (vowel length is important for distinguishing these meanings from the meaning oak tree; see Karttunen and Molina)
an oak tree; also, attested as a Nahuatl surname (Ahuatl) from 1560 (as in the Matrícula de Huexotzinco) and into the 19th c.; and then as Agua in the 20th c.
one of the boundaries of the Nonohualca of Tollan (Tula) Historia Tolteca-Chichimeca, 4v. Taken from the image of the folio published in Dana Leibsohn, Script and Glyph: Pre-Hispanic History, Colonial Bookmaking, and the Historia Tolteca-Chichimeca (Washington D.C.: Dumbarton Oaks, 2009), 65. Paleography and regularization of this toponym by Stephanie Wood.