noun [ U ]
1.
slices of bread that have been spread with butter :
a piece of bread and butter
2.
( informal ) a person or company's main source of income
noun [ U ]
1.
slices of bread that have been spread with butter :
a piece of bread and butter
2.
( informal ) a person or company's main source of income
Oxford Advanced Learner's English Dictionary. Оксфордский английский словарь для изучающик язык на продвинутом уровне. 2005