What is Income

• the financial gain (earned or unearned) accruing over a given period of time
• Income is the consumption and savings opportunity gained by an entity within a specified time frame, which is generally expressed in monetary terms. ...
• In U.S. business and financial accounting, the term "income" is generally defined by GAAP and the Financial Accounting Standards Board as: Revenues - Expenses; however, many people use it as shorthand for net income, which is the amount of money that a company earns after covering all of its ...
• Money one earns by working or capitalising off other people's work
• The amount of money received for labor, for services, from the sale of goods or property, or from investments.

Sources:
wordnetweb.princeton.edu/perl/webwn
en.wikipedia.org/wiki/Income
en.wikipedia.org/wiki/Income_(United_States_legal_definitions)
en.wiktionary.org/wiki/income