1. to make something start working or become active
2. to cause a chemical reaction or biological process to begin
Usage: scientific
3. to call military personnel or units into active service
Usage: military

Examples

• Press this button to activate the alarm system.
• You need to activate your credit card before using it.
• The enzyme activates when exposed to heat.
• The president decided to activate the National Guard.
• Double-click the icon to activate the software.
• Sunlight activates vitamin D production in the skin.
• The motion sensor will activate the lights automatically.