substratum
US /səbˈstræt̬.əm/
UK /səbˈstrɑː.təm/
名詞
基質
a layer of rock, soil, or similar material that is below another layer:
範例:
•
A substratum of clay kept moisture close to the topsoil.
基質
a layer of rock, soil, or similar material that is below another layer: