noun

An additive is a substance added to something in small amounts to improve, preserve, or alter it in some way. For example, food additives might be used to enhance flavor, color, or shelf life.

Example

1. The additive in the food coloring makes it more vibrant.
2. The additive in the fuel helps increase the engine's efficiency.
3. The additive in the shampoo helps to make your hair softer.