A normal is a 3D vector, and a 3D vector has three components, x, y, z. When you say you have a 3D vector that is "x=3, y=7, z=2", what you mean is that "it travels +3 units along the x axis, +7 units along the y axis and +2 units along the z axis". These x, y and z names refer to the "basis vectors". They're a set of…