The unearned revenue definition is relatively vague and often used in different contexts accrual accounting vs.cash accounting. In some circumstances it can apply to some situations and not to others. For example, it may mean that all income over a period of time is unearned and therefore tax free. In other circumstances it may apply to only some types of income, such as some types of dividends and interest.

Unearned income is also known as "in lieu of income". It refers to income earned by right of holding property without receiving an allowance or refund. Today, the phrase frequently refers to residual income obtained by virtue of ownership of real estate, inheritance, bonuses and other compensation received by public assistance. Another popular usage is to mean any income not subject to Federal tax. 
This includes various forms of self-employment (such as home-based businesses) and performance-based bonuses.