A Deployment is an outward movement of a body from its initial location to an extended region in an effort to accomplish a special purpose or mission.

In a Computer, a deployment is the step of placing or installing software on the target systems which includes configuration steps if necessary.

In the military, as defined by Joint Publication 1-02 , Department of Defense Dictionary of Military and Associated Terms, Deployment is 1. In naval usage, the change from a cruising approach or contact disposition to a disposition for battle. 2. The movement of forces within operational areas. 3. The outer positioning of forces into a formation for battle. 4. The relocation of forces and materiel to desired operational areas. Deployment encompasses all activities from origin or home station through destination, specifically including intra-continental United States, intertheater,and intratheater movement legs, staging, and holding areas.

In most of the world's navies, a deployment designates an extended period of duty at sea. The United States Navy recognizes those who complete deployments with a special decoration known as the Sea Service Deployment Ribbon.