elephant
n.— «Vale threw a party in Ulan Bator with samba dancers flown in from Brazil to mark the company’s arrival in Mongolia to search for another “elephant”—mining parlance for a big discovery.» —“Ivanhoe Seeks Riches Selling Output of Mongolian Mine to China” Bloomberg.com Oct. 27, 2004. (source: Double-Tongued Dictionary)
Further reading
There are eight major planets, but more than a million minor ones, including asteroids. If you discover one, you get the honor of naming it. The Dictionary of Minor Planet Names includes minor planets named for rock bands, jazz musicians, poets, and...
One of the celestial bodies listed in The Dictionary of Minor Planet Names(Amazon) is called Sumaura. It’s the name of the oldest private elementary school in Kobe, Japan, and was suggested by the discoverer’s son. This is part of a...