ayacachtli.

Headword: 
ayacachtli.
Principal English Translation: 

a rattle (see Lockhart, Karttunen), a gourd rattle (Sahagún)
James Lockhart, Nahuatl as Written: Lessons in Older Written Nahuatl, with Copious Examples and Texts (Stanford: Stanford University Press and UCLA Latin American Studies, 2001), 211.

Orthographic Variants: 
āyacachtli
IPAspelling: 
ɑːyɑkɑtʃtɬi
Alonso de Molina: 

ayacachtli. sonajas hechas a manera de dormideras.
Alonso de Molina, Vocabulario en lengua castellana y mexicana y mexicana y castellana, 1571, part 2, Nahuatl to Spanish, f. 3r. col. 2. Thanks to Joe Campbell for providing the transcription.

Frances Karttunen: 

ĀYACACH-TLI rattle / sonajas hechas a manera de dormideras (M) The Bf. 10v attestation is at variante in its vowel length pattern from all the other attestations, which are consistent across C,T,Z.R and X have the variant ĀYACAX-TLI.
Frances Karttunen, An Analytical Dictionary of Nahuatl (Norman: University of Oklahoma Press, 1992), 15.

Lockhart’s Nahuatl as Written: 

āyacachtli

Attestations from sources in English: 

Qujcujcatiaia, yn iveveiooan, qujteponacilhujaia, caiotzotzonjlia, caioujtequjlia, caiacachilhuja, comjchicaoacilhuja. = Her old men sang for her; they beat the two-toned wooden drum, and the turtle-shell drum; they rattled rattles shaped like dried poppy-seed pods, and they rattled bone rattles. (central Mexico, sixteenth century)
Fr. Bernardino de Sahagún, Florentine Codex: General History of the Things of New Spain; Book 1 -- The Gods; No. 14, Part 2, 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, 1950), 5.

ayacachtli (noun) = a musical instrument
Daniel Garrison Brinton, Ancient Nahuatl Poetry: Containing the Nahuatl Text of XXVII Ancient Mexican Poems (1887), 150.

Qujtitlantivi in vevetl, in aiacachtli, cujcanjme catca, qujpiquja, qujçaloaia, qujlnamjquja, qujioltevujaia in cujcatl: maviztic in qujpiquja. = They [the Tolteca] went about using the ground drum, the rattle stick. They were singers; they composed, originated, knew from memory, invented the wonderful songs which they composed. (central Mexico, sixteenth century)
Fr. Bernardino de Sahagún, Florentine Codex: General History of the Things of New Spain; Book 10 -- The People, No. 14, Part 11, 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), 169.

Molina describes a rattle made for bringing sleep, for making people sleepy. But Sahagún says the ayacachtli was used with the huehuetl to wake people up. It probably depended upon the manner in which it could be used.

auh ac colinjz ac qujiolitiz in vevetl, in aiacachtli, in vncan molnamjquj, in vncan moiocoia in teuatl, in tlachinolli = And who will move, who will put life into the drum, the gourd rattle where war is recalled (central Mexico, sixteenth century)
Fr. Bernardino de Sahagún, Florentine Codex: General History of the Things of New Spain; Book 6 -- Rhetoric and Moral Philosophy, No. 14, Part 7, 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), 23.

xicolinj xiciocoia in avillotl, in vevetl, in aiacachtli = Agitate, attend to the auillotl, the drum, the gourd rattle (central Mexico, sixteenth century)
Fr. Bernardino de Sahagún, Florentine Codex: General History of the Things of New Spain; Book 6 -- Rhetoric and Moral Philosophy, No. 14, Part 7, 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), 53.

xicmocujtlavi in vevetl, in aiacachtli yn ijxitiloca in atl, in tepetl = Care for the drum, for the gourd rattle which are the means of awakening the city (central Mexico, sixteenth century)
Fr. Bernardino de Sahagún, Florentine Codex: General History of the Things of New Spain; Book 6 -- Rhetoric and Moral Philosophy, No. 14, Part 7, 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), 74.

xicmocujtlavican in vevetl, in aiacachtli, anqujxitizque in atl in tepetl: auh ancaviltizque in tloque, naoaque = Take care of the drum, the gourd rattle: ye will awaken the city, and ye will gladden the lord of the near, of the nigh (central Mexico, sixteenth century)
Fr. Bernardino de Sahagún, Florentine Codex: General History of the Things of New Spain; Book 6 -- Rhetoric and Moral Philosophy, No. 14, Part 7, 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), 90.

IDIEZ morfema: 
āyacachtli.
IDIEZ traduc. inglés: 
a type of gourd rattle.
IDIEZ def. náhuatl: 
Ce tlamantli xihuitl tlen xochiyohua chipahuac huan huehueyac icuamecayo; quipiya itlacca zan achi tolontic; macehualli quitzintequi, quiquixtilia iyollo huan quihuatza, teipan quicalaquilia piltetzin zo yaya tecomitl iyollo; quitequihuia ica tlatziliniz. “Nomachicniuh quiamati mihtotiz ica ce ayacachtli ne tiopan quemman quixihuitlaliah totiotzin. ”
IDIEZ gramática: 
tlat.
themes: 
Music, Song, Dance
Sensory Perception (sound, smell, etc.)