Pay as you earn is a term that refers to a system of taxation where an employee's tax liability is deducted from their salary at source. This ensures that their taxes are paid as they earn, rather than being due in a lump sum at the end of the tax year. Some synonyms for pay as you earn include taxes deducted at source, withholding tax, and PAYE tax. Withholding tax refers to the practice of withholding a portion of income for tax purposes while PAYE tax is a specific term used in the UK to refer to the same system. These terms are commonly used in the discussion of taxation and financial matters.