Wiktionary
n. The seasonal movement of people, with their cattle or other grazing animals, to new pastures which may be quite distant.
Wikipedia
Transhumance is the seasonal movement of people with their livestock between fixed summer and winter pastures. In montane regions (vertical transhumance), it implies movement between higher pastures in summer and lower valleys in winter. Herders have a permanent home, typically in valleys. Generally only the herds travel, with a certain number of people necessary to tend them, while the main population stays at the base. In contrast, horizontal transhumance is more susceptible to being disrupted by climatic, economic or political change.
Traditional or fixed transhumance occurs or has occurred throughout the inhabited world, particularly Europe and western Asia. It is often of high importance to pastoralist societies, as the dairy products of transhumance flocks and herds ( milk, butter, yogurt and cheese) often form much of the diet of such populations. In many languages there are words for the higher summer pastures, and frequently these words have been used as place names: e.g. Hafod in Wales.
The term "transhumance" is also occasionally used in correlation with nomadic pastoralism – the regular migration of people and livestock over longer distances.