Serendipity means a «fortuitous happenstance» or «pleasant surprise». It was first coined by Horace Walpole in 1754. In a letter he wrote to a friend Walpole explained an unexpected discovery he had made by reference to a Persian fairy tale, The Three Princes of Serendip. The princes, he told his correspondent, were «always making discoveries, by accidents and sagacity, of things which they were not in quest of».
The notion of serendipity is a common occurrence throughout the history of scientific innovation such as Alexander Fleming’s accidental discovery of penicillin in 1928, and the invention of the microwave oven by Percy Spencer in 1945, to name but a few.
The word has been voted one of the ten English words hardest to translate in June 2004 by a British translation company. However, due to its sociological use, the word has been exported into many other languages.