Terminology
On conventional tandems, the front rider steers as well as pedals the bicycle and is known as the captain, pilot, or steersman; the rear rider only pedals and is known as the stoker, navigator, or rear admiral. On most tandems the two sets of cranks are mechanically linked by a timing chain and turn at the same rate. As time has moved on so has the use of 'Captain' and 'Stoker' as terms for riders of a tandem. As both are seen as riders the use of the words 'front rider' and 'rear rider' are far more descriptive to modern Tandem riders.
Read more about this topic: Tandem Bicycle