Definition
Ticktacktoo is simply a less common variant spelling of ticktacktoe, the classic game with 'X's and 'O's. It follows the same rules: two players alternate turns marking spaces on a 3x3 grid. The goal is still to achieve three of your symbols in a row (horizontally, vertically, or diagonally). The differing spelling does not affect the gameplay or overall concept. Consider it just a quirk in how some people write the word.