What does "number of inputs to each neuron" mean in Neural Network terms?
You are bypassing the "hidden layer": A neural network consists of three layers: Input layer, hidden layer, and output layer:



You may also have more than one hidden layer:


(source: mu-sigma.com)  

Though, in your case, since the number of hidden layers is not specified, it is safe to assume that there is just 1 hidden layer.

So, for example, in a 3:1 network, you have 1 output neuron, and 3 hidden neurons. The number of inputs shows the number of neurons in the input layer.