yacametztli (Mdz65r)
This iconographic example is a sign from the side of a bowl of octli (pulque, a mildly alcoholic beverage). See the various examples of octli, below and on the right, which have this same design. The "yacametztli" is a nose ornament (literally, nose-crescent, referring to one of the shapes that the moon can have). It is black, horizontal, and curling, somewhat reminiscent of a ram's horns.
Stephanie Wood
One can see the symbol on a pre-Columbian pot that once held octli (pulque) in a blog from the University of Leicester. Multiple examples also appear in the Codex Mendoza on folio 71 recto, where we see people consuming pulque. The yacametztli also appears in the Codex Tudela and the Codex Magliabecchiano, where the goddess Mayahuel wears the ornament in her nose. See the short article in Mexicolore, where Gael Ollivier points to the association with pulque deities who wear the ornament and have this insignia on their shields. It may be that this is more than just an iconographic symbol but also a glyph.
Stephanie Wood
c. 1541, or by 1553 at the latest
nose ornaments, narigueras, moon, luna, rabbits, conejos, pulque, octli
yacametztli. This shape recalls the moon-as-vessel that holds the rabbit in the Codex Borgia. Four hundred rabbits were divine spirits associated with pulque, a fermented beverage drunk on ceremonial occasions. According to museum signage, the remains of rabbits and miniature pulque vessels are among the findings in the Templo Mayor, as is this "lunar noseplug" called a yacametztli in Nahuatl. Photograph by Stephanie Wood, Museo del Templo Mayor, 15 February 2023.

yacametz(tli), nose ornament and pulque symbol, https://nahuatl.wired-humanities.org/content/yacametztli
la nariguera lunar, símbolo del pulque
Stephanie Wood
Codex Mendoza, folio 65 recto, https://digital.bodleian.ox.ac.uk/objects/2fea788e-2aa2-4f08-b6d9-648c00...
Original manuscript is held by the Bodleian Libraries, University of Oxford, MS. Arch. Selden. A. 1; used here with the UK Creative Commons, “Attribution-NonCommercial-ShareAlike 3.0 License” (CC-BY-NC-SA 3.0)
