Activate

To put a system, process, or capacity into its working state.

Reach for it when describing the specific action that makes something begin operating

A pressure drop will activate the building's reserve pump.

• everyday

  start

  you simply mean beginning operation

  not when Start misses the idea of enabling a previously inactive function.

• everyday

  switch on

  a person directly turns on a device

  not when Automatic or chemical processes are rarely switched on.

• warm

  energize

  new energy or enthusiasm is brought to people or work

  not when Energize is imprecise for a coded security function.

• professional

  enable

  a feature becomes available for later use

  not when Enabled equipment may remain idle until separately activated.

• professional

  trigger

  one event causes an immediate response

  not when Trigger emphasizes causation and can suggest an unintended reaction.

• literary

  set in motion

  you want to stress the beginning of a larger sequence

  not when This phrase is cumbersome for pressing one button.

• deactivate
• disable
• halt

• activate a feature

  Administrators can activate a feature after the privacy review.

• activate the alarm

  Smoke near either sensor will activate the alarm.

• activate automatically

  The pathway lights activate automatically at dusk.