de·tach·ment / diˈtachmənt/ • n. 1. the state of being objective or aloof: he felt a sense of detachment from what was going on.2. Mil. a group of troops, aircraft, or ships sent away on a separate mission: a detachment of Marines | the battalion went on detachment to Florida. ∎  a party of people similarly separated from a larger group: a truck containing a detachment of villagers.3. the action or process of detaching; separation: structural problems resulted in cracking and detachment of the wall.

Detachment

a body of troops; part of a fleet. See also detail.

Examples: detachment of actors, 1739; of cavalry, 1781; of ships; of troops, 1678; of witnesses, 1681.