an amount of money that you save to use later, especially when you have stopped working:
• Life insurance endowment policies are a great way to build up a family nest egg for the future.
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nest egg UK US noun [C] INFORMAL
► MONEY a sum of money that has been saved or kept for a special purpose: build (up)/create a nest egg »
Regular investment of small amounts of money is an excellent way of building a nest egg.
»a retirement nest egg
Financial and business terms. 2012.