1. Any agent that retards, delays or hinders
   "The chemical acted as a retarder in the curing process of the concrete";
   - retardant, retardent, retardation
    
2. A device or substance that slows down a process or reaction
   "The chemical retarder extended the setting time of the concrete"
    
3. (vehicles) a device used to slow a vehicle, especially a heavy truck, without using the main brakes
   "The truck's retarder helped maintain a safe speed on the steep descent"

Derived forms: retarders

Type of: agent

Encyclopedia: Retarder