WordWeb Online

1. Put in motion or move to act
   - trip, actuate, trigger, set off, spark off, spark, trigger off, touch off
    
2. Make active or more active
   "activate an old file"
    
3. Make more adsorptive
   "activate a metal"
    
4. Aerate (sewage) so as to favour the growth of organisms that decompose organic matter
   - aerate
    
5. Make (substances) radioactive

Derived forms: activating, activates, activated

See also: activation, activator

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

Antonym: inactivate

Encyclopedia: Activate