tramlines
/ˈtræmlaɪnz/noun
1- Brit. rails for a tramcar〈英〉电车轨道。
1.1
- informal a pair of parallel lines, in particular the long lines at the sides of a tennis court (enclosing the extra width used in doubles play) or at the side or back of a badminton court〈非正式〉（网球、羽毛球赛中）双打时球场两侧的加道。
1.2
- figurative an inflexible principle or course of action〈喻〉不可改变的原则, 坚定不移的行动方针。