Principal English Translation:
water pipe, aqueduct, canal (see Molina and attestations); literally, a water-road
Alonso de Molina:
aotli. caño de agua.
Alonso de Molina, Vocabulario en lengua castellana y mexicana y mexicana y castellana, 1571, part 2, Nahuatl to Spanish, f. 6v. col. 2. Thanks to Joe Campbell for providing the transcription.
Attestations from sources in English:
1615. años. yhcuac oquipehualtico. i ye quicuauhtzotzona huey aohtli in xuchimilcopa huitz = the year 1615, was when they began to drive piles in the great canal coming from Xochimilco (central Mexico, 1615)
Annals of His Time: Don Domingo de San Antón Muñón Chimalpahin Quauhtlehuanitzin, James Lockhart, Susan Schroeder, and Doris Namala, eds. and transl. (Stanford: Stanford University Press, 2006), 300–1.
yquac acico yn aotli Sant Juan = was when the aqueduct reached San Juan (early seventeenth century, central New Spain)
Annals of His Time: Don Domingo de San Antón Muñón Chimalpahin Quauhtlehuanitzin, James Lockhart, Susan Schroeder, and Doris Namala, eds. and transl. (Stanford: Stanford University Press, 2006), 28–29.
Attestations from sources in Spanish:
aotli, canal, acueducto, se compone de atl, agua y otli, camino
Rémi Siméon, Diccionario de la lengua náhuatl o mexicana (Mexico: Siglo XXI, 1996), xxviii.