Encyclopedia of Arda: The Golden

A title of the dragons Glaurung and Smaug, and of Ar-Pharazôn, the last King of Númenor and his royal city.

Armenelos	The City of the Kings of Númenor, that lay to the east of the Meneltarma near the centre of the island kingdom, is sometimes referred to as 'Armenelos the Golden', presumably in reference to its richly opulent architecture.
Ar-Pharazôn	The last of the Kings of Númenor brought Númenor to the height of its power and military might. Seeking the everlasting life that he imagined was to be found in the Undying Lands, and corrupted by Sauron, he led an armada to Aman, and so brought about the Downfall of his kingdom.
Glaurung	The Dragon Glaurung apparently earned the title 'Golden' because of his golden colour (he is also called the 'Gold-worm of Angband'), though it may also refer to the hunger for gold and treasure that he shared with all his kind.
Smaug	Like Glaurung, Smaug's title of 'Golden' seems to derive partly from his appearance (he was red-golden in colour) and partly from his love of gold. The title no doubt also reflects that fact that his underside was encrusted in gold from the hoard he kept in Erebor.

The Golden