t i t for tat

What does the saying "t i t for tat is fair play" mean? And where was it derived? We Chinese have a saying goes that "We will not attack unless we are attacked; if we are attacked, we will certainly counter-attack." Do these two sayings mean the same?

"Payment in kind; precise retaliation. Most authorities believe this expression was a corruption of 'tip for tap,' meaning 'a blow for a blow.' It was already in its current form in the sixteenth century..." From "Facts on File Dictionary of Cliches," second edition, edited by Christine Ammer, Checkmark Books, New York, 2006. Page 443.

The way I've heard the expression used: He gave t i t for tat. Yes, I believe "t i t for tat" would apply to the scenario you presented. But, in my opinion, "t i t for tat" more closely applies to a trivial situation. As I said, just the way it sounds to me.

The Oxford English Dictionary traces the phrase to the mid-sixteenth century, and adds "apparently a variation of tip for tap," which it traces back a century further.

The definition is concisely given: "One blow or stroke in return for another; an equivalent given in return (usually in the way of injury, rarely of benefit); retaliation."

It's possible that the origin in either case is echoic of the sound of a light slap.