Definitions for "nest egg"
Assets set aside for a large future expense, such as a college education or retirement.
An egg left in the nest to prevent the hen from forsaking it, and to induce her to lay more in the same place.
Money set aside in a special fund to be used for special occasions, or more commonly, for retirement; as, she set aside a large hunk of her salary every month and had a considerable nest egg for her retirement.
Operational code name for the British re-occupation of the Channel Islands - May 1945
Keywords:  quantity, money, sense, reserve, great
a fund of money put by as a reserve
a great expression for a quantity of money that is used primarily to give one a sense of financial security