to think that sb/sth is the main purpose of or the most important thing in your life :
She lives for her work.
After his wife died, he had nothing to live for.
to think that sb/sth is the main purpose of or the most important thing in your life :
She lives for her work.
After his wife died, he had nothing to live for.
Oxford Advanced Learner's English Dictionary. Оксфордский английский словарь для изучающик язык на продвинутом уровне. 2005