ilacatztli.

Headword: 
ilacatztli.
Principal English Translation: 

a spiral, a conch, something rolled up

Attestations from sources in English: 

ecailacatzcozcayo = "that which bears the spiral pattern of the wind"
Wimmer 2004, given in French in the Gran Diccionario Náhuatl; translation to English, SW)

ilacatzoa = to roll up, https://nahuatl.wired-humanities.org/content/ilacatzoa

tlamamatla ilacatztli = spiral staircase, https://nahuatl.wired-humanities.org/content/tlamamatla-ilacatztli