Définitions
1.NounThat which is central or fundamental, as to one's business, survival, or income; a staple or cornerstone."They will do some machining if you ask them, but sheet metal has always been their bread and butter."
2.NounThe basic requirements of living, such as food and housing.
3.NounUsed other than figuratively or idiomatically: see bread, butter.
4.InterjectionSaid when two people walking together are temporarily separated by an obstacle in order to indicate that they belong together.