The only free and comprehensive online etymological dictionary of the Spanish language
grado (1) m. & f. (Noun) "step"
12th cent. From Latin gradus 'id.' From Proto-Italic *grad- 'id.' From Proto-Indo-European *ghred(h)- 'id.'
In the 13th cent. also with the meaning "dignity," an analogy of a noble's gracious stride, which is the origin of the surnames Grado, Grados, Grade, Grada, Gradera, Gradín, and Gradillas; as well as the name El Grado for towns in Oviedo, Huesca, and Segovia.
Portuguese grado, Catalan grau, French grade, Italian grado, Romanian grad