From onze (“eleven”) + -eno.
onzeno m (feminine onzena, masculine plural onzenos, feminine plural onzenas)
- eleventh
c. 1250, Alfonso X, Lapidario, f. 14v:DEl onzeno grado del ſigno de tauro es la piedra aque dizen coral en latin […]- Of the eleventh degree of the sign of Taurus is the stone they call coral in Latin […]