A ~ of something is a small quantity or amount of it, especially if it is spread over a large area.
...a light ~ of snow...
N-SING: usu N of n
A ~ of something is a small quantity or amount of it, especially if it is spread over a large area.
...a light ~ of snow...
N-SING: usu N of n
Collins COBUILD. Толковый словарь английского языка для изучающих язык Коллинз COBUILD (международная база данных языков Бирмингемского университета) . 2012