Related Clues:

• Center X?
• Middle O?
• XXX center
• First ''O'' of O-O-O
• Part of a "Hollywood Squares" winner
• '-- Tac Dough'
• First correct ''Hollywood Squares'' square
• Start of a winning combination
• It can't be helped
• Middle O of O-O-O
• Nervous twitch
• Small spasm
• Tie __
• Tic-__-toe
• Middle square, say