backline
/ˈbæklaɪn/noun
1- a line marking the back of something, especially the area of play in a game（尤指比赛区域的）底线; 端线。
1.1
- Rugby the players lined out across the field behind a scrum or line-out【英橄】（争球或界外球）后列队员。
1.2
- the amplifiers used by a popular music group for guitars and other instruments, typically placed across the back of the stage（流行音乐乐队中用于吉他等乐器的）后台放大器。