The word "titty" is a colloquial and informal formation, emerging in the 18th century as a childish or familiar variant of "tit." "Tit" itself has Germanic roots, related to Old English "titt" and Middle Low German "titte," meaning teat or nipple. The reduplicated, diminutive "-y" ending gives "titty" a more informal, often vulgar, and sometimes infantilizing character compared to its source. Its journey reflects a pattern in English where blunt anatomical terms are softened or altered through sound play to create slang, though the resulting term often retains or acquires a coarse connotation.

This is a simplex word. It is a reduplicative or diminutive alteration of the word "teat" or "tit," both of which are of Germanic origin referring to a nipple or breast.