Common commercial examples of concentrated solutions are hydrochloric acid and sulfuric acid. Hand soap, soft drinks and liquid medicine are concentrated solutions commonly found in the household.
Concentrated solutions are best understood relative to dilute solutions. Solutions in general are mixtures in which one substance (the solute) is dissolved in another (the solvent). Medication, cleaning agents and beverages are all solutions. Dilute solutions have a relatively solute-to-solvent ratio. They contain more solvent than is present in an equal amount of concentrated solution. Tap water is an example of dilute solution. It contains scarce amounts of dissolved minerals.
Concentrated solutions, on the other hand, have a large amount of solute. Many of the products commonly used in homes are concentrated solutions. Batter, for example, has a high percentage of flour (the solute) dissolved in water (the solvent). Soft drinks have large amount of sugar dissolved in water. Dish soap, medicine, coffee and syrup are all concentrated solutions.
The terms "concentrated" and "dilute" are relative. To fully understand the composition of a solution, an individual needs to know the solubility of the solute in the solvent at a given temperature. For example, the solubility of NaCl in water is 6 moles per liter of solution. This is a concentrated solution. On the other hand, AgCl has a solubility in water of 0.00001 moles per liter of solution — making it a dilute solution.