Tic Tac Dough was a popular game show that aired from 1956 to 1959 and then again from 1978 to 1985. Contestants would answer trivia questions and then choose squares on a tic-tac-toe board, hoping to get three in a row. If they succeeded, they would win money and continue playing. The show was known for its catchy theme song and its charismatic host, Wink Martindale. One of the key elements of the game was the use of “tac” markers to place X’s and O’s on the board, hence the answer to the crossword question being “TAC“.