Solute, solvent, solution
A solution is a homogeneous mixture, and the two parts it is made from have names of their own. A solution is made up of one solvent and one or more solutes.
A solution
solvent + solute = solution
Which one is which
The two are told apart by amount, and by nothing else.
The solvent
Of the components mixed to make the solution, the one present in the larger amount is the solvent.
The solute
The remaining components are the solutes. There may be more than one of them.
Three you already know
salt + water = salt solution
copper sulphate + water = copper sulphate solution
sugar + water = sugar solution
The solvent is not always water
Water is the commonest solvent and every example above uses it, but nothing in the definition says it has to be. Later in this chapter iodine is dissolved in carbon tetrachloride and grease in kerosene, and in each of those the solvent is the one there is more of.