Node Description & Purpose:
The Divide family of nodes allows you to divide the colour/scalar/vector coming into the Input by the color/scalar/vector coming into Input 2. The division is component-wise, for example with a colour:
Input.red divided by Input 2.red
Input.green divided by Input 2.green
Input.blue divided by Input 2.blue
Division by zero, which is an invalid operation and causes problems for computers, is handled safely by the nodes. In the case of division by zero the node will divide the value by epsilon, which is a very small number greater than zero. If you don't know what this means, basically you will get a very large valid number output from the node which ensures that your network will continue to work. If this was not done you could get either an invalid number which would cause problems in the rest of your network, or the application might even crash.
Node Type: Function
All nodes in this family have 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.
A vector is a set of three scalars, normally representing X, Y and Z coordinates. It also commonly represents rotation, where the values are pitch, heading and bank.