The term that defines new substances formed from chemical reactions is products.

Here's why:

* Reactants: The substances that go into a chemical reaction.

* Products: The new substances that are formed as a result of the chemical reaction.

For example:

Reactants: Hydrogen (H₂) + Oxygen (O₂)

Products: Water (H₂O)

The chemical reaction between hydrogen and oxygen produces a new substance, water.