1. to make something start working or become active
Usage: third person singular present tense of ‘activate’
2. to cause a chemical reaction or biological process to begin
Usage: scientific context

Examples

• She activates the alarm system before leaving the house.
• The motion sensor activates the outdoor lights automatically.
• Heat activates the chemical reaction in the mixture.
• The enzyme activates when it reaches the right temperature.
• He activates his phone by pressing the power button.
• Sunlight activates vitamin D production in the skin.
• The security guard activates the emergency protocol during the drill.