Two or more forms of matter mixed but not chemically joined is called a mixture.

Here's why:

* Not chemically joined: This means the substances in the mixture retain their individual properties. They haven't reacted to form new compounds.

* Mixed: The substances are physically combined, but their individual components are still distinguishable.

Examples of mixtures:

* Salt and pepper: You can easily see the separate grains of salt and pepper.

* Sand and water: Sand settles to the bottom, and water remains liquid.

* Air: A mixture of gases like nitrogen, oxygen, and carbon dioxide.

Let me know if you'd like to know more about different types of mixtures!