Series of periodic money payments made to a person who retires from employment because of age, disability, or the completion of an agreed span of service. The payments generally continue for the rest of the recipient's natural life, and they are sometimes extended to a widow or other survivor. Military pensions have existed for many centuries; private pension plans originated in Europe in the 19th century. There are two basic types of pension plans: defined contribution and defined benefit. A defined contribution plan invests a defined amount each pay period. The individual may have some discretion as to how the money is invested. The benefit, the amount of the pension, depends on the success of those investments. A defined benefit plan pays a known amount according to some formula, but the amount invested in the fund may vary. Pensions may be funded by making payments into a pension trust fund or by the purchase of annuities from insurance companies. In plans known as multiemployer plans, various employers contribute to one central trust fund administered by a joint board of trustees.