staff of life, the

Some critical necessity or basic staple. Said especially of staple foods like bread or rice. We want our employees to know that respectful discussion and debate are the staff of life around here. The widespread infection of potatoes—the staff of life in Ireland at the time—caused a nationwide famine that killed over a million people.

A staple or necessary food, especially bread. For example, Rice is the staff of life for a majority of the earth's people. This expression, which uses staff in the sense of "a support," was first recorded in 1638.

Bread; sometimes, by extension, any essential food. Understandably this term originated in the Bible (“the stay and the staff, the whole stay of bread,” Isaiah 3:1). However, it was not until the eighteenth century that the staff of life was definitively identified with bread (prior to that it had often been corn, the British term for wheat). “Bread, dear brothers, is the staff of life,” wrote Jonathan Swift (A Tale of a Tub, 1704), and so it has remained.