(~s)
A ~ is a flat piece of soft material that you put between two joined surfaces in a pipe or engine in order to make sure that gas and oil cannot escape.
N-COUNT
(~s)
A ~ is a flat piece of soft material that you put between two joined surfaces in a pipe or engine in order to make sure that gas and oil cannot escape.
N-COUNT
Collins COBUILD. Толковый словарь английского языка для изучающих язык Коллинз COBUILD (международная база данных языков Бирмингемского университета) . 2012