In the context of spike sorting "Unit" is often used.  One Unit is not necessary one Neuron. You can have 2 wells separated "Units" + 1 multi "Unit" after a spike sorting. At the apposite, you can also have 2 electrodes recording the same neuron at 2 different positions, with respective SpiekTrain. Thomas was in favor of Unit. Personalty, I do not care so much.