APAD: Bread and butter

"Bread and butter" generally refers to a simple, staple food combination, but idiomatically, it represents a person's main source of income, livelihood, or basic necessities. It also describes essential, "bread-and-butter" issues or tasks. Historically, it signifies sustenance and comfort, stemming from medieval times as a staple meal.

In livelihood, bread and butter refers to the core activity that provides income, represents fundamental, reliable, or foundational elements.

The phrase dates back to the early 1700s, stemming from the idea of bread and butter as a basic, essential food. It signifies the fundamental necessities required for survival.

"Bread and butter" is also a superstitious blessing or charm, typically said by young couples or friends walking together when they are forced to separate by an obstacle, such as a pole or another person. By saying the phrase, the bad luck of letting something come between them is thought to be averted. Both walkers must say the phrase, and if they do not do this, then a bitter quarrel is expected to occur. The concept derives from the difficulty of separating butter from bread once it has been spread – buttered bread cannot be "unbuttered".