Proper noun
Secchi (plural Secchis)
A surname from Italian.
Secchi classes Secchi spectral types (152 Schjellerup is Y Canum Venaticorum During the 1860s and 1870s, pioneering stellar spectroscopist Angelo Secchi created the Secchi classes in order to classify observed spectra. Source: Internet
The roman numerals used for Secchi classes should not be confused with the completely unrelated roman numerals used for Yerkes luminosity classes. Source: Internet