* States of Matter: This is the most general and accurate way to refer to them.
* Phases of Matter: This term is often used interchangeably with "states of matter."
* Physical States: This is another way to describe the different forms matter can take.
You could also use the terms "solid," "liquid," and "gas" individually, depending on the context. For example, you might say "the three states of matter are solid, liquid, and gas."