Tic-tac-toe (American English), noughts and crosses (British English), or Xs and Os is a paper-and-pencil game for two players.

A simple game where you have to collect a specified number of consecutive zeros or crosses. You can choose the size of the playing field and the length of the winning sequence. The default field size is 10x10 cells. The winner is the one who collects 5 symbols in a line.

The different names of the game are more recent. The first print reference to "noughts and crosses" (nought being an alternative word for zero), the British name, appeared in 1858, in an issue of Notes and Queries.[9] The first print reference to a game called "tick-tack-toe" occurred in 1884, but referred to "a children's game played on a slate, consisting in trying with the eyes shut to bring the pencil down on one of the numbers of a set, the number hit being scored". "Tic-tac-toe" may also derive from "tick-tack", the name of an old version of backgammon first described in 1558. The US renaming of "noughts and crosses" as "tic-tac-toe" occurred in the 20th century.