发动 (fā dòng) is a compound verb meaning 'to start' or 'to set in motion' — most commonly used for starting engines (e.g., a car or motorcycle) or launching organized initiatives like campaigns, movements, or projects. The first character 发 (fā) carries meanings related to 'emit', 'initiate', or 'issue', while 动 (dòng) means 'to move' or 'to act'. Together, they emphasize the act of initiating movement or action from a state of rest or inactivity.

This word is formal and intentional: it implies deliberate activation, not accidental or spontaneous onset. It’s frequently heard in transportation contexts ('Start the car'), political or social discourse ('launch a public awareness campaign'), and technical settings ('activate the system'). It is not used for everyday actions like turning on lights (use 打开) or beginning a meal (use 开始). As a transitive verb, it usually takes a direct object (e.g., 发动汽车, 发动战争), though context may omit it when clear.