A solution is a mixture of two or more substances in a single
phase. At least two substances must be mixed in order to have
a solution. The substance in the smallest amount and the one
that dissolves or disperses is called the SOLUTE. The substance
in the larger amount is called the SOLVENT. In most common instances
water is the solvent. The gases, liquids, or solids dissolved
in water are the solutes.
In the graphic, the blue bottle is a homogeneous solution
mixture of water, KOH, glucose, oxygen gas dissolved, and methylene
blue - an indicator.