noun
[ sing. ] a layer of ozone high above the earth's surface that helps to protect the earth from harmful radiation from the sun
noun
[ sing. ] a layer of ozone high above the earth's surface that helps to protect the earth from harmful radiation from the sun
Oxford Advanced Learner's English Dictionary. Оксфордский английский словарь для изучающик язык на продвинутом уровне. 2005