1. Plural of flutterboard; boards or devices that flutter or vibrate, often used in swimming training or water sports to help develop leg strength and technique.
Usage: chiefly used in swimming and aquatic training contexts; also called flutter kicks or kickboards in some contexts

Examples

• The swim coach handed out flutterboards to all the beginners for their leg-strengthening drills.
• Using flutterboards during practice helps swimmers develop better ankle flexibility.
• The pool was filled with young athletes holding flutterboards as they practiced their flutter kicks.
• Flutterboards are essential training equipment in most competitive swimming programs.