[oy vay]

While rereading Norman Davies’s Europe: A History, I ran across “Livy’s catch phrase, Vae victis! (Woe to the vanquished),” and it suddenly dawned on me that the most ubiquitous of Yiddish phrases, oy vay, means literally “Oh, woe!” Which is always what it seemed to mean, but I had no idea it came from the Latin.