1. Rendered active; e.g. rendered radioactive, luminescent, photosensitive or conductive
   "The activated carbon effectively filtered the water"; "The scientist worked with activated isotopes"
    
2. (of sewage) treated with aeration and bacteria to aid decomposition
   "The activated sludge process is commonly used in wastewater treatment plants"
    
3. (military) set up and placed on active assignment
   "a newly activated unit"

1. Make active or more active
   "activate an old file"
    
2. Put in motion, initiate (a device, reaction, circuit, etc)
   "activate the circuits";
   - trip, actuate, trigger, set off, spark off, spark, trigger off, touch off
    
3. Make more adsorptive
   "activate a metal"
    
4. Aerate (sewage) so as to favour the growth of organisms that decompose organic matter
   "The treatment plant activated the wastewater to speed up the purification process";
   - aerate
    
5. Make (substances) radioactive
   "The scientists activated the isotope in the particle accelerator"

See also: active, treated

Type of: alter, change, initiate, modify, pioneer

Antonym: deactivate

Encyclopedia: Activated