A four-in-hand is a carriage drawn by four horses that has the reins rigged in such a way that it could be driven by a single driver. Before the four-in-hand rigging was developed, two drivers were needed to handle four horses. In fact, with a four-in-hand, the solo driver could handle all four horses by holding all the reins in one hand, thus the name four-in-hand.

The four-in-hand knot used to tie neckwear may have developed from a knot used in the rigging of the reins.