noun
[ U , C ] ( physics ) a technique for examining sound, light, vibration , etc., by looking at the different wave frequencies produced
noun
[ U , C ] ( physics ) a technique for examining sound, light, vibration , etc., by looking at the different wave frequencies produced
Oxford Advanced Learner's English Dictionary. Оксфордский английский словарь для изучающик язык на продвинутом уровне. 2005