ic omilhuitl semana.

(a loanword from Spanish)

ic omilhuitl semana.
Principal English Translation: 

Monday, the second day of the week (see Molina)
(partly a loanword from Spanish, semana, week)

Orthographic Variants: 
icomilhuitl semana
Alonso de Molina: 

icomilhuitl semana. el lunes.
Alonso de Molina, Vocabulario en lengua castellana y mexicana y mexicana y castellana, 1571, part 2, Nahuatl to Spanish, f. 33v. col. 1. Thanks to Joe Campbell for providing the transcription.