If you steadied something, you made it still or stopped it from moving.
Steadied things are usually safe and not moving around.
Examples:
She steadied the wobbly table.
He steadied the ladder so it wouldn't fall.
The old man steadied himself on the railing.
I steadied the big stack of books so they wouldn't fall over.
The superhero steadied the shaking building with his strong hands.
The cat steadied the ball on its nose without letting it fall.