Tit for tat, why tit and why tat

Question

I was wondering why the term tit for tat contains the word tit as in titts, and what does tat mean anyway?

Thank you.

Answer 1

'Tit' and 'tat' are both the names of small blows which originated as 'tip' and 'tap'. These are recorded by Charles, Duke of Orleans in a book of poems that he wrote while captive in England after the battle of Agincourt and first published circa 1466:

"Strokis grete, not tippe nor tapp."

The widespread unconcern about spelling and pronunciation in the Middle Ages led to 'tip', 'tap', 'tit' and 'tat' all to be variant spellings. John Heywood appears to be the first to have used 'tit for tat', in the parable The Spider and the Flie, 1556:

"That is tit for tat in this altricacion [altercation]."

In the 20th century, 'tit for tat' was the source of the Cockney rhyming slang 'titfer', meaning hat. The renowned lexicographer of slang Eric Partridge listed that in 1930, in Songs & Slang of the British Soldier:

Tit-for, tit-for-tat, that is, hat.

This usage was popularised by the British comedian Tommy Trinder who, although he was born several miles from the sound of Bow Bells, in Streatham, London, and hence not strictly a cockney, exemplified cockney style to most people. He was rarely seen in public without his titfer tat.

https://www.phrases.org.uk/meanings/tit-for-tat.html

Answer 2

The phrase seems to come from something like "tap for tap" - a small blow in exchange for receiving a small blow. There's an article discussing the origin here: http://www.worldwidewords.org/qa/qa-tit1.htm