The term RESERVE FUND refers to a fund set aside for future use. The crossword solutions for this term are KITTY (5 letters), NESTEGG (7 letters), and MADMONEY (8 letters). KITTY is a slang term for money saved up, NESTEGG is a metaphor for a savings account, and MADMONEY is an informal term for money that can be used for discretionary spending. All three of these terms refer to the concept of a reserve fund.