The definition of an adage is a saying that has come to be accepted as truth over time.
"The grass is always greener on the other side" is an example of an adage.
an old saying that has been popularly accepted as a truth
Origin of adageFrench ; from Classical Latin adagium, adagio ; from ad-, to + aio, I say ; from an unverified form agyo ; from Indo-European base an unverified form ??-, speak, say