# Mare

Also called: maria, lunar seas.

One of the Moon's dark, smooth plains — ancient lava flows, once mistaken for seas.

The dark patches that make the “man in the Moon” are maria (singular mare, Latin for sea): vast basins flooded by dark basalt lava more than three billion years ago. The bright regions between them are older, cratered highlands.

Binoculars show them easily; a telescope reveals wrinkle ridges, rilles (collapsed lava channels) and the smaller craters that pepper them.

**Examples:** [moon](https://astropilot.space/object/moon.md)

**Related:** [Crater](https://astropilot.space/glossary/crater.md), [The Moon](https://astropilot.space/glossary/the-moon.md), [Terminator](https://astropilot.space/glossary/terminator.md)

From the AstroPilot astronomy glossary: https://astropilot.space/glossary/mare