What is a white whale slang?

A white whale slang refers to a rare or hard-to-find item or achievement. It is a term commonly used in collecting communities, such as coin collectors or book collectors, to refer to an item that is highly sought after but difficult to obtain. The term "white whale" is derived from Herman Melville's novel "Moby-Dick," in which Captain Ahab is obsessed with hunting down and killing the elusive white whale.

In popular culture, the term has been widely adopted to refer to any personal or professional goal that seems unattainable but is still pursued with great determination. It can also be used to describe a person's ultimate dream or ambition.

Overall, a white whale slang is symbolic of a challenging and coveted pursuit that may require perseverance, dedication, and luck to achieve.