grundpfeiler (sache)

listen to the pronunciation of grundpfeiler (sache)
Немецкий Язык - Английский Язык
bread and butter
That 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.

{i} maintenance, livelihood, source of income
{s} habitual, routine, usual; practical, material
the financial means whereby one lives; "each child was expected to pay for their keep"; "he applied to the state for support"; "he could no longer earn his own livelihood"
Bread and butter issues or matters are ones which are important to most people, because they affect them personally. The opposition gained support by concentrating on bread-and-butter matters
Something that is the bread and butter of a person or organization is the activity or work that provides the main part of their income. The mobile phone business was actually his bread and butter