The status of being in the military reserves after completing active duty; first reserve service subject to mobilization.
彼は大学卒業後に現役を務め、現在は予備役にある。
After serving on active duty following university graduation, he is now in the reserves.
予備役として年に数回、訓練に参加する必要がある。
As a reservist, you need to participate in training several times a year.