Related Clues:

• See 20-Across
• 'Aha!'
• 'Understand?'
• 'I understand!'
• 'Right on, brother!'
• 'Gotcha'
• Cry of success
• Understood
• Code name
• Walkie-talkie word
• 'Oh, I see'
• 'Right on!'
• '___ that!'
• Trucker's approval
• Catch phrase?