to gradually become smaller, quieter, etc. and then end :
The campaign petered out for lack of support.
The road petered out into a dirt track.
to gradually become smaller, quieter, etc. and then end :
The campaign petered out for lack of support.
The road petered out into a dirt track.
Oxford Advanced Learner's English Dictionary. Оксфордский английский словарь для изучающик язык на продвинутом уровне. 2005