Why is the ninth month called September?
late 14c., from Old French aparant "evident, obvious, visible," from Latin apparentem (nominative apparens) "visible, manifest," present participle of apparere (see appear). First attested in phrase heir apparent (see heir). Meaning "superficial" is c.1400. Apparent magnitude in astronomy (how bright a heavenly body looks from earth, as opposed to absolute magnitude, which is how bright it really is) is attested from 1875.