This expression means to retaliate against some sort of attack or injury. The expression is posted this week as a companion to a review of the book “The World Set Free” by H. G. Wells. The book, written in 1913, describes how atomic bombs are used to destroy Paris and an aviator sets out with three atomic bombs to drop on Berlin, “tit for tat.”

The expression was used as early as 1556 and may have been variations in how to say “this for that.” Also, “tit and tat” are “…both the names of small blows that originated as ‘tip and tap’.”