expanse
/ɪkˈspæns/noun
1- an area of something, typically land or sea, presenting a wide continuous surface广阔的地域（或海域等）; 广阔, 浩瀚：
the green expanse of the forest.
绿色的林海。
1.1
- the distance to which something expands or can be expanded扩张距离; 膨胀量：
the moth has a wing expanse of 20 to 24 mm.
那只蛾的翅展达20至24毫米。
词源
mid 17th cent.: from modern Latin expansum 'something expanded', neuter past participle of expandere （see EXPAND）.