Black swan is the event that is a surprise (to the observer) and has a major impact.“黑天鹅”事件指突然发生并且产生巨大影响的事件。The term black swan was a Latin expression—its oldest known reference comes from the poet Juvenal's characterization of something being "a rare bird in the lands, and very like a black swan."“黑天鹅”是一个拉丁短语，其最早的出处是诗人尤文纳尔（译者注：尤文纳尔为罗马讽刺派诗人）在诗中将某个事物描绘为“世间罕有之鸟，酷似黑天鹅”。