omipilli.

Headword: 
omipilli.
Principal English Translation: 

forty cloths, pieces of paper mats, or tortillas, etc. (things that are flat and thin) (see Molina)

IPAspelling: 
oːmihpilli
Alonso de Molina: 

omipilli. quarenta mantas, pliegos de papel, esteras o tortillas. &c.
Alonso de Molina, Vocabulario en lengua castellana y mexicana y mexicana y castellana, 1571, part 2, Nahuatl to Spanish, f. 76v. col. 1. Thanks to Joe Campbell for providing the transcription.

Attestations from sources in English: 

The construction is 2 x 20 = 40.

themes: 
Numbers, Math