the first beat of a musical measure (as the conductor's arm moves downward)
downbeat详细解释
down.beat
n.(名词) Music The downward stroke made by a conductor to indicate the first beat of a measure. 【音乐】 强拍:乐队指挥向下的手势表示一个节拍的第一拍 Informal A period of stagnation or inactivity. 【非正式用语】 停滞:迟钝的或不活泼的期间 adj.(形容词) Cheerless; pessimistic. 忧郁的;悲观的