mare

UK: /ˈmɛə^r/ US: /mɛr/ ,(mâr; Astron. mär′ā, mâr′ē)

Inflections of 'mare' (n): npl: maria

WordReference Random House Learner's Dictionary of American English © 2025

mare¹ /mɛr/   n. [countable]

1. a female horse or donkey.

ma•re³ /ˈmɑreɪ, ˈmɛri/   n. [countable] , pl. ma•ri•a 

/ˈmɑriə, ˈmɛr-/.  
1. Astronomy a large, dark plain found on the moon.

WordReference Random House Unabridged Dictionary of American English © 2025

mare¹  (mâr), n. 

1. a fully mature female horse or other equine animal.

• bef. 900; Middle English, variant of mere, Old English m(i)ere; cognate with Dutch merrie, German Mähre, Old Norse merr; akin to Old English mearh, Old Norse marr, Irish marc horse. See marshal

mare²  (mâr), n. [Obs.]

1. nightmare (def. 3).

• bef. 900; Middle English, Old English; cognate with German Mahre, Old Norse mara. See nightmare

ma•re³  (mär′ā, mâr′ē), n., pl. ma•ri•a (mär′ē ə, mâr′-). [Astron.]

1. Astronomy any of the several large, dark plains on the moon and Mars: Galileo believed that the lunar features were seas when he first saw them through a telescope.

• Latin: sea
• 1680–90

Mar.E., 

1. Marine Engineer.

Collins Concise English Dictionary © HarperCollins Publishers::

mare / mɛə/ noun

1. the adult female of a horse or zebra

Etymology: 12th Century: from Old English, of Germanic origin; related to Old High German mariha, Old Norse merr mare

mare / ˈmɑːreɪ -rɪ/ noun ( maria / ˈmɑːrɪə/)

1. (capital when part of a name) any of a large number of huge dry plains on the surface of the moon, visible as dark markings and once thought to be seas: Mare Imbrium (Sea of Showers)
2. a similar area on the surface of Mars, such as Mare Sirenum

Etymology: from Latin: sea