Here's a breakdown:

* Solubility: The ability of a substance (solute) to dissolve in another substance (solvent).

* Soluble: A substance that can dissolve in a solvent. Examples include sugar in water, salt in water, and alcohol in water.

* Insoluble: A substance that does not dissolve in a solvent. Examples include sand in water, oil in water, and chalk in water.

It's important to note that "insoluble" is not an absolute term. Most substances have some degree of solubility, even if it's extremely low.