English Dictionary
Definition black swan in British English
black swan noun
[countable] noun
/ˌblæk ˈswɒn/
When Dutch explorer Willem de Vlamingh first saw black swans in Western Australia in the 17th century, Europeans believed that all swans were white, so a black swan seemed an impossibility. The term came to be used for an event that happens even though it seems impossible.
1
an event that is extremely rare and unexpected but has very significant consequences
