People or things that make something more steady or stable.
Steadiers are usually helpful because they make things safer or more reliable.
Examples:
The big rocks are the steadiers for the little bridge.
The teacher's hand is the steadiers for the student's hand.
The new tires make the car steadiers.
The kind words are the steadiers for her sad heart.
The superhero is the steadiers for the city.
The big tree is the steadiers for the small plants.