What Do Bread And Butter Mean?

'Bread and butter' is phrase that means a source of income or one's livelihood. It is used to describe how one earns money for his food, to pay the rental charges for his housing and to bring up his kids. This phrase could also be used in the following way: to quarrel with one's bread and butter. This phrase means 'to complain about one's source of livelihood'. This phrase carries yet another meaning which says, 'to act against one's best interests'. Example: He has to slog day and night to earn his bread and butter.

This phrase 'bread and butter' can also be used as an adjective and only before a noun. Example: a bread and butter product or and issue. Such a product is that which concerns most basic and very important needs.

'It's my bread and butter.' -> 'It is what pays my bills.' (so the sentence refers to a job)

Examples:
A teacher says: Teaching is what pays my rent. It is my bread and butter.
An architect says: Houses buy my groceries. They're my bread and butter.

It is your job.

It means when the money pays for the bills or rent its my bread and butter

To work hard enough. It is a phrase from when slaves where around. If they worked hard enough they would get food