Deployment is a word, often used by the military, for sending troops into duty. A soldier could be part of a deployment to the Middle East.
Deployment refers to assigning people to serve in various locations, especially soldiers and other military personnel. A deployment may include soldiers, as well as equipment and generals. Deployments might be part of a war or a peaceful mission. Also, non-military organizations use this word too: they might speak of a deployment of workers to a new office. When you see the word deployment, you know people are being sent somewhere for a specific mission.
the distribution of forces in preparation for battle or work