A yoke is a wooden beam sometimes used between a pair of oxen or other animals to enable them to pull together on a load when working in pairs, as oxen usually do; some yokes are fitted to individual animals. There are several types of yoke, used in different cultures, and for different types of oxen. A pair of oxen may be called a yoke of oxen, and yoke is also a verb, as in "to yoke a pair of oxen". Other animals that may be yoked include horses, mules, donkeys, and water buffalo. Etymology The word "yoke" is believed to derive from Proto-Indo-European *yugóm (yoke), from root *yewg- (join, unite), and is thus cognate with yoga. This root has descendants in almost all known Indo-European languages including German Joch, Latin iugum, Ancient Greek ζυγόν (zygon), Persian یوغ (yuğ), Sanskrit युग (yugá), Hittite 𒄿𒌑𒃷 (iúkan), Old Church Slavonic иго (igo), Lithuanian jungas, Old Irish cuing, and Armenian լուծ (luts), all meaning "yoke". Neck or bow yoke A bow yoke is a shaped wooden crosspiece bound to the necks of a pair of oxen (or occasionally to horses). It is held on the animals' necks by an oxbow, from which it gets its name. The oxbow is usually U-shaped and also transmits force from the animals' shoulders. A swivel between the animals, beneath the centre of the yoke, attaches to the pole of a vehicle or to chains (traces) used to drag a load. Bow yokes are traditional in Europe, and in the United States, Australia and Africa. Head yoke A head yoke fits onto the head of the oxen. It usually fits behind the horns, and has carved-out sections into which the horns fit; it may be a single beam attached to both oxen, or each ox may have a separate short beam. The yoke is then strapped to the horns of the oxen with yoke straps. Some types fit instead onto the front of the head, again strapped to the horns, and ox pads are then used for cushioning the forehead of the ox (see picture). A tug pole is held to the bottom of the yoke using yoke irons and chains. The tug pole can either be a short pole with a chain attached for hauling, or a long pole with a hook on the end that has no chain at all. Sometimes the pole is attached to