Nouns denoting natural objects (not man-made)

planetary nebula
a nebula that was once thought to be a star with its planets but is now thought to be a very hot star surrounded by an expanding envelope of ionized gases that emit a fluorescent glow because of intense radiation from the star
 
Strait of Georgia
the strait separating Vancouver Island from the Canadian mainland
 
Colorado River
an important river in the southwestern United States; rises in the Rocky Mountains of northern Colorado and flows southwest through Utah into Arizona (where it flows through the Grand Canyon) and then southward through the southern tip of Nevada, then forming the border between California and Arizona and finally into Mexico where it empties into the Gulf of California; the main source of water in the southwestern United States
 
trail
a track or mark left by something that has passed
 
sky
the atmosphere and outer space as viewed from the earth
 
Old Faithful
a geyser in Yellowstone National Park that erupts for about 4 minutes about every 65 minutes
 
cutting
a piece cut off from the main part of something
 
dale
an open river valley (in a hilly area)
 
Vela
a constellation in the southern hemisphere between Carina and Pyxis
 
Arauca
a river that rises in northern Colombia and flows generally eastward to the Orinoco in central Venezuela
 
cave
a geological formation consisting of an underground enclosure with access from the surface of the ground or from the sea
 
Moray Firth
an inlet of the North Sea on the northeast coast of Scotland
 
Inside Passage
a naturally protected waterway from Seattle to Skagway in southeastern Alaska
 
adjunct
something added to another thing but not an essential part of it
 
Jebel Musa
a promontory in northern Morocco opposite the Rock of Gibraltar; one of the Pillars of Hercules
 
Aquila
a constellation in the Milky Way near Cygnus; contains the star Altair
 
Trinity River
a river in eastern Texas that is formed near Dallas and flows generally southeastward to Galveston Bay
 
mantle
anything that covers
 
Namoi River
a river in southeastern Australia that flows generally northwest to join the Darling River
 
giant star
a very bright star of large diameter and low density (relative to the Sun)
 
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