Amphoteric oxides are metal oxides that show the properties of both acidic and basic oxides, i.e., they react with both acids and bases. Example: Aluminium oxide (Al₂O₃) and zinc oxide (ZnO).
The answer is directly from Chapter 3 ("What you have learnt"): "Aluminium oxide and zinc oxide show the properties of both basic as well as acidic oxides. These oxides are known as amphoteric oxides." Examiners expect the definition plus at least one example for full marks.