H. P. Grice, "The morality of morality"

mos , mōris, m. etym. dub.; perh. root ma-, measure; cf.: maturus, matutinus; prop., a measuring or guiding rule of life; hence, I.manner, custom, way, usage, practice, fashion, wont, as determined not by the laws, but by men's will and pleasure, humor, self-will, caprice (class.; cf.: consuetudo, usus). I. Lit.: “opsequens oboediensque'st mori atque imperiis patris,” Plaut. Bacch. 3, 3, 54: