Which word refers to making repayment or returning?

The term that most accurately refers to making repayment or returning is "reimburse." This word specifically denotes the act of compensating someone for money that they have spent or a financial obligation that has been incurred. It implies a clear transaction where an amount is paid back, restoring financial balance to the involved parties.

In the options provided, "reciprocate" typically refers to the notion of responding to a gesture or action with a corresponding act, which may not involve a repayment context. "Requite" often relates to returning a favor, but it doesn't strictly connotate the financial aspect of repayment. "Restore," on the other hand, generally means to bring something back to its original condition or state, but it doesn't specifically imply financial repayment. Therefore, "reimburse" is the most fitting choice, as it directly pertains to the act of returning funds or compensating an expense incurred.