quiddity
noun [ U ] social science specialized uk/ˈkwɪd.ɪ.ti/ us/ˈkwɪd.ə.t̬i/
本质，实质
the basic nature or quality of something, that makes it different from other things
Reading about a subculture like swimming provides an opportunity to appreciate the idiosyncratic details and quiddity of the sport. 阅读诸如游泳这样的亚文化，可以让我们有机会领略到这项运动独特的细节和本质。
Synonym: essence (IMPORTANCE)