Strengthener (noun)

1. A device or substance that is used to make something stronger.
2. A person or thing that gives strength or support.

Origin:

From the english strengthen + -er.

Examples:

1. The weightlifter used the strengthener to build muscle mass.
2. The brace was a strengthener that helped to support her injured ankle.
3. The vitamin supplement was a strengthener for her immune system.
4. The strengthener helped to fortify the structure of the building.
5. The coach was a strengthener for the team, helping them to build confidence and motivation.