Related Clues:

• Nervous twinge
• Middle X, maybe
• First O, maybe
• Tic-toe connector
• Opening in "Hollywood Squares"
• Tic-toe linkup
• Washington's Sea-___ Airport
• Half a Washington airport?
• Involuntary muscle movement
• Contraction of a sort
• First X or O, say
• One-third of a game win
• Tic __
• Bad liar's giveaway
• Mannerism or spasm