white whale

Meanings

1. Synonym of beluga (“the beluga whale, Delphinapterus leucas, a cetacean found in the Arctic Ocean”)
2. Any whale of the family Monodontidae, which comprises the beluga whales and narwhals (Monodon monoceros), and some extinct species.
3. An obsession, a monomania.
4. A printing plate, used to manufacture a particular sports card, that is then issued as a collectible itself.

Etymology

From white + whale. The figurative senses refer to the novel Moby-Dick (1851) by the American writer Herman Melville (1819–1891), in which Captain Ahab relentlessly pursues a rare albino sperm whale.