Principal English Translation:
someone; one part, part of something, a separate part, a certain quantity (see Molina, Karttunen, and Lockhart)
Alonso de Molina:
cequi. algo, o alguna parte delo que estaua entero.
Alonso de Molina, Vocabulario en lengua castellana y mexicana y mexicana y castellana, 1571, part 2, Nahuatl to Spanish, f. 18v. col. 1. Thanks to Joe Campbell for providing the transcription.
Frances Karttunen:
CEQUI pl: CEQUĪN~CEQUĪNTĪN some, a separate part / algo, o alguna parte de lo que estaba entero (M), algunos, o los unos (M for cequintin) The long vowel of the second syllable in plural forms is abundantly attested in B and C . The long vowel of the final syllable of the longer plural form is given here by analogy with plurals of other quantifiers. It is not directly attested as long.
Frances Karttunen, An Analytical Dictionary of Nahuatl (Norman: University of Oklahoma Press, 1992), 32.
Lockhart’s Nahuatl as Written:
quantifier. some, a certain quantity, one part. cequīn, cequīntin pl., some, a certain number of people or animals. oc cequīntin, others.
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), 214.
Attestations from sources in English:
cequi ... cequi = half this and half that (implies equal parts);
cequi yc = with some of it
Robert Haskett and Stephanie Wood's notes from Nahuatl sessions with James Lockhart and subsequent research.
Attestations from sources in Spanish:
cequi = algún; parte de algo; cequintin, cequin = algunos, los unos
Joseph Augustin de Aldama y Guevara, Arte de la lengua mexicana (Mexico: BIbliotheca Mexicana, 1754), 29.