(substrata)
A ~ of something is a layer that lies under the surface of another layer, or a feature that is less obvious than other features. (FORMAL)
...its deep ~ of chalk...
N-COUNT: with supp, usu N of n
(substrata)
A ~ of something is a layer that lies under the surface of another layer, or a feature that is less obvious than other features. (FORMAL)
...its deep ~ of chalk...
N-COUNT: with supp, usu N of n
Collins COBUILD. Толковый словарь английского языка для изучающих язык Коллинз COBUILD (международная база данных языков Бирмингемского университета) . 2012