icelilocatzin sanctissimo sacramento.

(a loanword from Spanish)

icelilocatzin sanctissimo sacramento.
Principal English Translation: 

communion, or the receipt of the holy sacrament
(partly a loanword from Spanish)

Alonso de Molina: 

icelilocatzin sanctissimo sacramento. la comunion, o recibimiento del sanctissimo sacramento.
Alonso de Molina, Vocabulario en lengua castellana y mexicana y mexicana y castellana, 1571, part 2, Nahuatl to Spanish, f. 32r. col. 1. Thanks to Joe Campbell for providing the transcription.

Attestations from sources in English: 

Susanne Klaus states that this is a neologism.
Susanne Klaus, Uprooted Christianity: The Preaching of the Christian Doctrine in Mexico, Based on Franciscan Sermons of the 16th Century Written in Nahuatl (Bonn: Bonner Amerikanistische Studien e. V. c/o Seminar für Völkerkunde, Universität Bonn, 1999), 251.