A small stand or holder on which chopsticks are placed when not in use, similar to 箸置き (はしおき).
See also: 箸置き
食事のときは箸台に箸を置いてください。
Please place your chopsticks on the chopstick rest during the meal.
Compound of 箸 (はし, 'chopsticks') and 台 (だい, 'stand').