in a way that shows that sth is completely certain :
The research showed beyond doubt that smoking contributes to heart disease.
( law )
The prosecution was able to establish beyond reasonable doubt that the woman had been lying.
in a way that shows that sth is completely certain :
The research showed beyond doubt that smoking contributes to heart disease.
( law )
The prosecution was able to establish beyond reasonable doubt that the woman had been lying.
Oxford Advanced Learner's English Dictionary. Оксфордский английский словарь для изучающик язык на продвинутом уровне. 2005