boon
/buːn/noun
1
- usu. in sing. a thing that is helpful or beneficial恩惠; 裨益：
the route will be a boon to many travellers.
这条通道将方便许多游客。
2
- archaic a favour or request〈古〉恩泽; 请求。
词源
Middle English （originally in the sense 'request for a favour'）： from Old Norse bón.