Definition of "apothegm"

Every glaſs of wine, or bit almoſt, that I committed to my mouth, ſhe uſhered thither with ſome Apothegm or other: the whole ſeries, indeed, of her diſcourſe, was compoſed of nothing but reaſon or wit, which made me admire her; which ſhe eaſily underſtood, I perceived by her ſmiles, when ſhe obſerved me gaping, as it were, when ſhe ſpoke, as if I would have eaten up her Words.

1665, Richard Head, The English Rogue: Deſcribed, in the Life of Merington Latroon, A Witty Extravagant, Being a Compleat Hiſtory of the Moſt Eminent Cheats of Both Sexes, Henry Marsh, page 355

The account which he [James Ferguson] himself gives of these observations is exceedingly interesting, and strikingly brings out the ingenuity of his mind, and his determination to allow no difficulties of circumstances to stand in his way. [...] Thus we are reminded of the apothegm that where there's a will there's a way—an apothegm which has found illustration in every department of effort, but nowhere more frequently than in the progress of science and art.

1866, W[illiam] K[ing] Tweedie, “James Ferguson. 1710–1776.”, in Youthful Diligence, Future Greatness: A Book for the Young, London, Edinburgh, New York, N.Y.: T[homas] Nelson and Sons, […], pages 273–274

"You are too wonderful!" he would say. "How do you find time for everything?"She rejoined with the apophthegm that made the rounds of Riseholme next day."My dear, it is just busy people that have time for everything."

1920, E. F. Benson, Queen Lucia, George H. Doran Company, pages 10-11

For the gods have withheld from the barbarians the light of discretion, as that their poetry is not, like ours, full of choice apophthegms and useful maxims, but is all of love and war.

1954, C. S. Lewis, chapter 8, in The Horse and His Boy, Collins, published 1998

Which means roughly that business keeps one safe from love—ominous talk when one’s lover is a courtesan. I hoped that it was just another literary conceit I ought to know. (It is, I later learned, an apothegm by Ovid.)

2008, Dave Duncan, The Alchemist’s Apprentice, Ace Books, page 114