candle wick (literally, candle heart)
(partially a loanword from Spanish)
Alonso de Molina:
candela yollotli. pauilo de candela
.Alonso de Molina, Vocabulario en lengua castellana y mexicana y mexicana y castellana, 1571, part 2, Nahuatl to Spanish, f. 12v. col. 1. Thanks to Joe Campbell for providing the transcription.