lead-off
/ˈliːdɒf/adjective
1- (of an action) beginning a series or a process（连续活动）开头的, 开端的：
the album's lead-off track.
该唱片专辑的开头部分。
1.1
- Baseball denoting the first batter in a line-up or of an inning【棒球】第一位击球员的; 第一棒的。