someone's bread and butter
bread and butter
1. noun A vital component of something. Bread and butter, as foodstuffs, are considered basic forms of sustenance. A flourishing stock market is the bread and butter of a successful country.
2. noun A job or task that provides one with a steady income. I'm an artist on the weekends, but being a tutor is my bread and butter.
3. adjective Providing financial stability. The phrase can be hyphenated when used as an adjective. I love any writing assignment where I can be creative, but I always make sure to pick up some bread-and-butter gigs to pay the bills.
4. adjective Typical or common. The phrase can be hyphenated when used as an adjective. My sister worries about everything, even the bread-and-butter tasks of everyday life.
someone's bread and buttersomeone's livelihood; routine work to provide an income.
1998 Times It is not that the smaller deal has disappeared—they remain the bread and butter of this industry.