A curious aspect of this system is that dark, smooth areas are named as seas, bays and lakes. When, after the invention of the telescope, the surface of the Moon was first seen in detail, it was thought that these really were bodies of water. Although we now know that they are areas of younger rock, the tradition of giving them aquatic names has continues. Here they are with their meanings, starting with the seas (Maria):

Mare Australe	Southern Sea
Mare Crisium	Sea of Crises
Mare Fecunditatis	Sea of Fertility
Mare Frigoris	Sea of Cold
Mare Humboldtianum	Humboldt's Sea
Mare Humorum	Sea of Moisture
Mare Imbrium	Sea of Showers
Mare Marginis	Marginal Sea
Mare Nectaris	Sea of Nectar
Mare Nubium	Sea of Clouds
Mare Orientale	Eastern Sea
Mare Serenitatis	Sea of Serenity
Mare Smythii	Smyth's Sea
Mare Spumans	Foaming Sea
Mare Tranquillitatis	Sea of Tranquility
Mare Undarum	Sea of Waves
Mare Vaporum	Sea of Vapours
Oceanus Procellarum	Ocean of Storms
Sinus Aestuum	Seething Bay
Sinus Iridium	Bay of Rainbows
Sinus Medii	Central Bay
Sinus Roris	Bay of Dews
Palus Epidemarium	Marsh of Diseases
Palus Nebularium	Marsh of Mists
Palus Putredinis	Marsh of Decay
Palus Somnii	Marsh of Sleep
Lacus Mortis	Lake of Death
Lacus Somniorum	Lake of the Dreamers

Latin terms are also used (with greater accuracy) for dry land features such as -

Rima / Rimae	rille / rilles	eg Rima Ariadaeus
Rupes	scarp	eg Rupes Recta
Mons / Montes	mountain / mountains	eg Montes Haemus
Vallis	valley	eg Vallis Schröteri
Catena	crater chain	eg Catena Davy
Dorsum / Dorsa	wrinkle ridge(s)	eg Dorsa Smirnov

Inconstant Moon