semitono.

(a loanword from Spanish)

Headword: 
semitono.
Principal English Translation: 

a half tone (in music) (see attestations)

Attestations from sources in English: 

This is attested in a seventeenth-century Guatemalan music manuscript. It is paired with centlacoltuzquitl which the translators give to mean "medio tono."
Fernando Horcasitas y Alfred Lemmon, "El Tratado de Santa Eulalia: un manuscrito musical náhuatl," Tlalocan 12 (1997), 94–95.