motto (n.)

1580s, "word or phrase on an emblem explaining or emphasizing its symbolic significance; phrase or short sentence inscribed on something used to indicate the tenor of that to which it is attached," from Italian motto "a saying, legend attached to a heraldic design," from Late Latin muttum "a grunt; a word," from Latin muttire "to mutter, mumble, murmur" (see mutter). Meaning "proverbial pithy maxim adopted by someone as a rule of conduct" is from 1796. Motto-kiss "candy wrapped in fancy paper having a motto or scrap of poetry enclosed with it" is from 1858.