1.  pension fund(n = noun.possession) superannuation fund - a fund reserved to pay workers' pensions when they retire from service;
is a kind of fund, monetary fund

2.  pension fund(n = noun.group) - a financial institution that collects regular contributions from employers to provide retirement income for employees;
is a kind of nondepository financial institution

closed-end fund, endowment fund, fund, fund raise, hedge fund, imprest fund, index fund, international monetary fund, monetary fund, mutual fund, old-age pension, open-end fund, pension, pension account, pension off, pension plan, reserve fund, retirement fund, retirement pension, revolving fund, sinking fund, slush fund, superannuation fund, trust fund, united nations children's fund