A homogeneous mixture in which one substance is dissolved in another is known as a solution.

Here's a breakdown:

* Homogeneous mixture: A mixture where the components are evenly distributed throughout.

* Dissolved: One substance (the solute) is completely dispersed within another substance (the solvent).

Examples:

* Saltwater: Salt (solute) dissolved in water (solvent).

* Sugar in coffee: Sugar (solute) dissolved in coffee (solvent).

* Air: Various gases (solutes) dissolved in nitrogen (solvent).