Adage
Etymology
From Latin "adagium," "a proverb" or "saying," generally traced to "ad," "to," combined with an element related to "aio," "I say." The word arrived in English partly through Erasmus’s famous Renaissance collection of classical proverbs, the "Adagia." An adage carries the weight of tradition rather than any named author, which is both its strength and its blind spot.
noun · /AD-ij/
A traditional saying that expresses a widely accepted observation or piece of folk wisdom.
What it names
The proverb whose authority comes purely from age and repetition — worth weighing precisely because "everyone has always said so" is a weak reason for believing anything.
Example
The old adage that you should never meet your heroes exists because it keeps being confirmed.
Related idea
An adage is folk wisdom hardened by time; a maxim is a rule of conduct, telling you not just how things are but what to do.