Refers to that income source, or group of sources, that makes up the largest proportion of an individual's total income.
Refers to that component which constitutes the largest proportion of an income recipient's total income. Various combinations of income sources can be used to derive this classification. For example, at the most detailed level, the income sources are combined into five components: wages and salaries, self-employment income (farm and non-farm), government transfer payments, investment income, and other income. The absolute values for these components are compared and the largest one is designated as the major source of income.