Node Description & Purpose:
The Dot product node takes the Input and Input 2 vectors and outputs the dot product of the two vectors, which is a scalar value. The dot product is the cosine of the angle between the two input vectors.
Node Type: Function
This node has just the one setting, which lets you choose a node for Input 2.
A scalar is a single number. 1, 200.45, -45, -0.2 are all examples of scalar values.