Select the most appropriate meaning of the given idiom.
Bread and butter

The correct answer is Livelihood.

Explanation:
The idiom "bread and butter" refers to a person's livelihood or their main source of income, which provides the basic necessities of life (like food and shelter).
Let us look at the given options:
1. Breakfast: This refers to the first meal of the day. While bread and butter can be eaten for breakfast, it is not the idiomatic meaning of the phrase.
2. Sharing: This means dividing or distributing something among others, which is unrelated to this idiom.
3. Livelihood: This refers to the means of securing the necessity of life (income or employment). This matches the idiomatic meaning perfectly.
4. Party: This refers to a social gathering, which is completely unrelated.
Therefore, the most appropriate meaning of the idiom "bread and butter" is Livelihood.