1. A tax-free reinvestment of a distribution from a qualified retirement plan into an IRA or other qualified plan within a specific time frame, usually 60 days. These transfers can happen when leaving a job at an employer who offered a retirement plan such as a 401(k) plan. The company can issue a check for the amount minus 20% in withheld taxes. To avoid this penalty, the rollover must be done trustee to trustee, meaning that the check is made out to the new trustee or custodian of the rollover IRA. The company will provide the check and the participant must deposit the check into the new account within 60 days. also called IRA rollover. 2. More generally, a movement of funds from one investment to another.