wobble board

 

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wobble board

Wikipedia

wobble board (plural wobble boards)

1. An item of exercising equipment which challenges the sportsman to balance his weight on it as it could tilt in any direction.

   Hypernym: balance board

2. A musical instrument consisting of a flat board which is held in the hands and shaken so that the board flexes in order to produce a rhythmic "whoop-whoop" noise.