lodestar
noun [ S ] uk/ˈləʊd.stɑːr/ us/ˈloʊd.stɑːr/
指示方向的星星;（尤指）北极星
a star, especially the Pole Star, used to help find direction
literary范例，规范；指导原则
an example or principle that people want to follow
The party manifesto is no longer the lodestar it used to be. 该党的宣言已经不再是行动的指南了。