Domestic sheep (Ovis aries) are quadrupedal, cloven-hoofed mammals of the genus Ovis. They are the most numerous ovine species, and most likely descended from wild mouflon. Sheep were one of the earliest animals domesticated for agricultural purposes; primarily for their valuable fleece and meat. A sheep's wool is the most widely used of any animal, and is typically harvested by shearing. Ovine meat is called "lamb" when from younger animals and "mutton" when from older ones. They continue to be vital livestock internationally, and are occasionally raised for pelts, as dairy animals, and as model organisms by science.
Sheep husbandry is practiced globally, and has played an important role in many economies throughout time, most notably Australia, New Zealand, Patagonian nations, and the United Kingdom in the modern era. Sheep raising has a large lexicon of unique terms which differ considerably by region. Use of the name "sheep" began in Middle English as a derivation of the Old English word scēap; it is both the singular and plural name for the animal. A group of sheep is called a flock, herd or mob. Adult female sheep are referred to as ewes, intact males as rams, castrated males as wethers, and younger sheep as lambs. Many other specified terms for the various life stages of sheep exist, generally related to lambing, shearing, and age.
Being a key animal in the history of farming, the sheep has a deeply entrenched place in human culture, and finds representation in much modern language and symbology. As livestock, sheep are most-often linked to pastoral, Arcadian imagery. Sheep figure in many mythologies—such as the Golden Fleece—and major religions, especially the Abrahamic traditions. In both ancient and modern religious ritual, sheep are used as sacrificial animals. In contemporary English language usage, people who are timid, easily led, or stupid are often compared to sheep.