Tic-Tac-Toe is a 2-player game played on a 3x3 grid. Players take turns placing their marks (X or O) in empty squares. The first player to get 3 of their marks in a row (horizontally, vertically, or diagonally) wins.

Here is a more detailed description:

Tic-Tac-Toe is a simple game that can be played by people of all ages.
The game is played on a 3x3 grid.
Each player takes turns placing their mark (X or O) in an empty square.
The first player to get 3 of their marks in a row (horizontally, vertically, or diagonally) wins.
If all 9 squares are filled and no player has 3 of their marks in a row, the game is a draw.