Definition
The scalar product, also known as the dot product, is a way to multiply two vectors and get a single number (a scalar) as the result. Think of it as measuring how much two vectors point in the same direction. If they point in exactly the same direction, you get a large positive scalar. If they are perpendicular, you get zero. If they point in opposite directions, you get a negative scalar. It’s like combining forces: if they align, the result is strong; if they oppose, the result is weak.