A proverb (from Latin: proverbium) is a simple and insightful, traditional saying that expresses a perceived truth based on common sense or experience. Proverbs are often metaphorical and use formulaic language. A proverbial phrase or a proverbial expression is a type of a conventional saying similar to proverbs and transmitted by oral tradition. The difference is that a proverb is a fixed expression, while a proverbial phrase permits alterations to fit the grammar of the context. Collectively, they form a genre of folklore.

Some proverbs exist in more than one language because people borrow them from languages and cultures with which they are in contact. In the West, the Bible (including, but not limited to the Book of Proverbs) and medieval Latin (aided by the work of Erasmus) have played a considerable role in distributing proverbs. Not all Biblical proverbs, however, were distributed to the same extent: one scholar has gathered evidence to show that cultures in which the Bible is the major spiritual book contain "between three hundred and five hundred proverbs that stem from the Bible," whereas another shows that, of the 106 most common and widespread proverbs across Europe, 11 are from the Bible. However, almost every culture has its own unique proverbs.