Mare

Mare is a term with several distinct uses in English and related fields. In equestrian contexts, a mare is an adult female horse, typically used for breeding or riding. A mare is considered mature enough to reproduce, with the male equivalent being a stallion and a castrated male a gelding. Common terms distinguish age and role, such as filly for a young female horse and colt for a young male. The word appears in various breeding and riding phrases, and mare status can influence management and training decisions.

In astronomy, mare (plural maria) refers to large, dark plains on the Moon. The term comes from Latin mare, meaning “sea,” a naming convention adopted by early astronomers who thought the basaltic plains resembled seas. These features are not water bodies; they are ancient volcanic plains formed when lava filled large impact basins. The lunar maria cover substantial portions of the lunar near side and contribute to the Moon’s characteristic appearance. Notable examples include Mare Tranquillitatis (Sea of Tranquility), Mare Serenitatis (Sea of Serenity), Mare Imbrium (Sea of Showers), and Mare Nubium (Sea of Clouds), with most surfaces dating to about 3 to 4 billion years ago.

Other uses of the term exist as well. Mare can be a personal name in some languages and cultures and may appear in various place names. The word’s meanings are thus context-dependent, ranging from animal husbandry to planetary geology.