剧中男主指的fifty shades什么意思

fifty shades
《五十度灰》
双语对照
例句:
1.
Fifty shades of greysales soar despite critical disdain.
尽管颇受非议，《五十度灰》（Fifty Shades of Grey）一书的销量却一路扶摇而上。

2.
Google: "fifty shades of grey," by e.l. james, is a 201