noun

• 1A mainly black swan with white flight feathers which is common in Australia and Tasmania and has been introduced elsewhere.

  Cygnus atratus, family Anatidae

• 2An unpredictable or unforeseen event, typically one with extreme consequences.

  ‘the bank industry's vulnerability to black swans’

  More example sentences

  • ‘black swan events always look eminently predictable in hindsight, yet no one ever predicts them’

• 3Something extremely rare.

  More example sentences

  • ‘husbands without faults, if such black swans there be’