Reciprocal (adjective)

1. Mutual or given in return for something received.
2. Related to or denoting a relationship or action that is reciprocal.
3. Related to or denoting a quantity that is the reciprocal of another.

Origin:

The word "reciprocal" comes from the latin word "reciprocus" which means "moving back and forth" or "alternate" which came into use in the late 16th century. the word was used to describe something that is given or done in return for something received and it is mutual.

Examples:

1. The countries have a reciprocal agreement on trade.
2. The reciprocal of 2 is 0.5.
3. The relationship between the two countries is reciprocal.
4. We had a reciprocal arrangement with our neighbors where we would take care of each other's pets while away on vacation.
5. The exchange program is based on reciprocal visits.