ciyaua. nitla. (pret. onitlaciauh.) remojar algo. Alonso de Molina, Vocabulario en lengua castellana y mexicana y mexicana y castellana, 1571, part 2, Nahuatl to Spanish, f. 22r. col. 2. Thanks to Joe Campbell for providing the transcription.
Frances Karttunen:
CIYĀHU(A) vt to soak something, to water something / remojar algo, o regar la hortaliza (M) [(3)Tp.202]. By analogy with the nouns ĀYAHU(I)-TL ‘cloud’ CEPAYAHU(I)-TL ‘snow,’ and QUIYAHU(I)-TL ‘rainstorm’ one would expect a short A in the second syllable, but T has the reflex of Ā. CIYĀHUILIA applic. CIYĀHU(A) CIYĀHUALŌ nonact. CIYĀHU(A) Frances Karttunen, An Analytical Dictionary of Nahuatl (Norman: University of Oklahoma Press, 1992), 35.