Serendipity means a "fortunate happenstance" or "pleasant surprise". It was 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, the invention of the Post-it note by Spencer Silver in 1968.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.The first noted use of "serendipity" (meaning pleasant surprise) in the English language was by Horace Walpole (17171797). In a letter to Horace Mann (dated 28 January 1754) he said he formed it from the Persian fairy tale The Three Princes of Serendip, whose heroes "were always making discoveries, by accidents and sagacity, of things they were not in quest of". The name stems from Serendip, an old name for Sri Lanka (aka Ceylon), from Tamil Ceralamdivu, Sanskrit Simhaladvipa and Persian Sarandp (). Parts of Sri Lanka were under the rule of Tamil kings for extended periods of time in history. Kings of Kerala, India (Cheranadu) were called Ceran Kings and divu, tivu or dheep means island, the island belonging to the Chera King was called Cherandeep, hence Sarandib by Arab traders.Serendipity is not just a matter of a random event, nor can it be taken simply as a synonym for "a happy accident" (Ferguson, 1999; Khan, 1999), "finding out things without being searching for them" (Austin, 2003), or "a pleasant surprise" (Tolson, 2004) ..The New Oxford Dictionary of English defines serendipity as the occurrence and development of events by chance in a satisfactory or beneficial way, understanding the chance as any event that takes place in the absence of any obvious project (randomly or accidentally), which is not relevant to any present need, or in which the cause is unknown.Innovations presented as examples of serendipity have an important characteristic: they were made by individuals able to "see bridges where others saw holes" and connect events creatively, based on the perception of a significant link.The chance is an event, serendipity a capacity. The Nobel Prize laureate Paul Flory suggests that significant inventions are not mere accidents.The serendipitous can play an important role in the search for truth, but is often ignored in the scientific literature because of traditional scientific behavior and scientific thinking based on logic and predictability.Successful researchers can observe scientific results with careful attention to analyzing a phenomenon under the most diverse and different perspectives. They can question themselves on assumptions that do not fit with empirical observations. Realizing that serendipitous events can generate important research ideas, these researchers recognize and appreciate the unexpected, encouraging their assistants to observe and discuss unexpected events.Serendipity can be achieved in groups where a "critical mass" of multidisciplinary scientists work together in an environment that fosters communication, establishing the idea that the work and the interest of a researcher can be shared with others who may find a new application for new knowledge.Various thinkers discuss the role that luck can play in science. One aspect of Walpole's original definition of serendipity, often missed in modern discussions of the word, is the need for an individual to be "sagacious" enough to link together apparently innocuous facts in order to come to a valuable conclusion. Indeed, the scientific method, and the scientists themselves, can be prepared in many other ways to harness luck and make discoveries.