Capital gains tax is a term used to describe the tax levied on the profits earned from selling capital assets like stocks, property, or bonds. There are many other common synonyms for this term, including capital tax, profit tax, investment income tax, or simply the capital gains levy. Other words often used to refer to this type of tax include growth tax, appreciation tax, and return tax. No matter what term is used, this tax is designed to ensure that individuals pay their fair share of taxes on the profits they earn from investments and other forms of capital.