(~s)
1.
Reinforcements are soldiers or policemen who are sent to join an army or group of police in order to make it stronger.
...the despatch of police and troop ~s.
N-PLURAL
2.
The ~ of something is the process of making it stronger.
I am sure that this meeting will contribute to the ~ of peace and security all over the world...
N-VAR: oft N of n