Principal English Translation:
both together (see Molina and Karttunen); jointly
Alonso de Molina:
neuan. ambos ados, o juntamente ambos ados.
Alonso de Molina, Vocabulario en lengua castellana y mexicana y mexicana y castellana, 1571, part 2, Nahuatl to Spanish, f. 71r. col. 1. Thanks to Joe Campbell for providing the transcription.
Frances Karttunen:
NEHUĀN both together / ambos a dos o juntamente ambos a dos (M) M gives as a separate entry the plural form neuantin. T has a short vowel in the second syllable, but B and C mark it long. This is generally, but not necessarily, possessed, ĪNNEHUĀN 'the two of them.' The phrase NEHUĀN ĒHUAH appears in C and M meaning 'they are siblings.' See NE-, -HUĀN.
Frances Karttunen, An Analytical Dictionary of Nahuatl (Norman: University of Oklahoma Press, 1992), 163.
Horacio Carochi / English:
-nehuān = both together
Horacio Carochi, S.J., Grammar of the Mexican language with an explanation of its adverbs (1645), translated and edited with commentary by James Lockhart, UCLA Latin American Studies Volume 89 (Stanford: Stanford University Press, UCLA Latin American Center Publications, 2001), 507.
Lockhart’s Nahuatl as Written:
complex relational word. with the pl. possessive prefixes. both, both together.
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), 226.
Attestations from sources in English:
niquinCahuilia ymonehuan quitocas Se xihuil tlamis oc sepa oc Se quitocas = I leave it to them jointly; one is to sow it one year and stop, and the other is to sow it again (San Pedro Calimaya, Toluca Valley, 1759) Caterina Pizzigoni, ed., Testaments of Toluca (Stanford: Stanford University Press and UCLA Latin American Center Publications, 2007), 205.
tonehua = the two of us together
Robert Haskett and Stephanie Wood's notes from Nahuatl sessions with James Lockhart and subsequent research.