What is the term for a mature female sheep?

A mature female sheep is called a ewe. The word distinguishes her from a ram, an intact adult male; a wether is a castrated male, while a lamb is a young sheep of either sex.

Ewes are central to flock reproduction and usually give birth to lambs after a gestation of about five months. Depending on breed, nutrition, and management, a ewe may produce one or more lambs in a season. Sheep farming terminology developed alongside pastoral agriculture, so age, sex, and reproductive status each have their own traditional name.

A common mix-up is using “female sheep” and “ewe” interchangeably at every age. In ordinary livestock usage, “ewe” generally means a mature female, while a young female may be called a ewe lamb. The related term “sow” belongs to pigs, not sheep. Sheep themselves were domesticated thousands of years ago and are kept especially for wool, meat, and milk.