anecuyotl.

Headword: 
anecuyotl.
Principal English Translation: 

uncertain meaning; the roots suggest something like a watery honey (from atl + necuhtli), but this term is translated by Garibay as ceñidero, and by Anderson and Dibble as "paper crowns;" López Austin and López Luján explain that it is a headdress adorned with feathers (see attestations for more)

Orthographic Variants: 
aneucyotl, anecuiotl, anecuiyotl, anecúyotl, anecuhyotl
Attestations from sources in English: 

a paper crown adorned with feathers
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), 69.

This crown was part of the garb of the image of Huitzilopochtli, who was placed on a carved wooden "serpent bench" (coatlapechtli; said by López Austin and López Luján to be a bier, andas) decorated with fish amaranth dough, wearing a sleeveless jacket decorated with paintings of human bones. He also had cape of maguey fiber and a cape of red spoonbill feathers and a red eye border and a golden disc at the middle. With his figure, piled hip high, were bones made of more fish amaranth dough and called teomimilli. Covering these fake bones was a cape decorated with paintings of skulls, palms of hands, hip bones, ribs, legs, lower arm bones, and the outlines of feet. This cape was called tlaquaquallo. Finally, he had a special loin cloth called the "sacred roll" made of white paper, thick and long, supported by ceremonial arrows hardened in fire and decorated with white turkey feathers.
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), 69.

qujncuili in jntlatquj, in jnnechichioal in anecuiotl = he took from them their vestments, their adornment, their paper crowns ornamented with feathers (central Mexico, sixteenth century)
Fr. Bernardino de Sahagún, Florentine Codex: General History of the Things of New Spain; Book 3 -- The Origin of the Gods, Part IV, 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, 1978), 4.

anecuyotl = a belt made of feathers with a cone at the back
Miguel León-Portilla, The Broken Spears: The Aztec Account of the Conquest of Mexico (2006).

The traditional spelling is anecuyotl. But A. Wimmer and Molly Bassett both prefer aneucyotl, just as Basset believes teuctli is preferable over tecuhtli.
Molly H. Bassett, The Fate of Earthly Things: Aztec Gods and God-Bodies (2015), ch. 4, note 2.

Attestations from sources in Spanish: 

"Prenda característica del dios Huitzilopochtli. En el mito de su nacimiento, el anecúyotl pertenecía originalmente a los centzonhuitznáhuah; ero, tras derrotarlos, Huitzilopochtli se apoderó de ésta y otras divisas. Era un tocado con armazón de papel, en forma de cono truncado con la paarte ancha hacia arriba, cubierto de plumas de diversos colores, y con plumas blancas colgantes a manera de cabellos de peluca. En la parte superior tenía un mástil que remataba en un cuchillo ensangrentado en una de sus mitades, todo esto elaborado con pluma.... En E 1-2 se da como sinónimo xinapállotl. En C 10 se dice que el anecúyotl de la image de tzoalli es de hechura de pluma, 'rollizo, algo ahusado, algo estrecho en su parte inferior." Ver esta fuente para mucho más información.
Alfredo López Austin y Leonardo López Luján, Monte Sagrado--Templo Mayor (México: Instituto Nacional de Antropología e Historia y Instituto de Investigaciones Antropológicas de la Universidad National Autónoma de México, 2009), 498.