in the united states the 401(k) plan or individual retirement account is a defined plan
In the United States, a 401(k) plan is the tax-qualified, defined-contribution pension account defined in subsection 401(k) of the Internal Revenue Code. Under the plan, retirement savings contributions are provided (and sometimes proportionately matched) by an employer, deducted from the employee's paycheck before taxation (therefore tax-deferred until withdrawn after retirement or as otherwise permitted by applicable law), and limited to a maximum pre-tax annual contribution of $18,500 (as of 2018).