self-acting aid
nounUK /ˌself ˈæktɪŋ eɪd/
US /ˌself ˈæktɪŋ eɪd/
A self-acting aid is a tool that helps you by itself, without you doing anything.
The self-acting aid on the door closes it gently all by itself.
RELATED WORDS
OTHER MEANINGS
2. A machine or gadget that works on its own to assist people.
The self-acting aid in the kitchen stirs the soup without anyone watching.
3. A built-in feature that helps something run automatically.
This self-acting aid keeps the room at the right temperature.
4. A helper that starts working by itself when needed.
The self-acting aid turns on the light when it gets dark.