柯林斯詞典substratum /s?b?strɑ?t?m, -?str?t?m/ (substrata) 1. N-COUNT A substratum of something is a layer that lies under the surface of another layer, or a feature that is less obvious than other features. 底層[正式] [with supp, usu N 'of' n] ...its deep substratum of chalk. ...它的深層的白堊底土。 返回 substratum