deja vu - the experience of thinking that a new situation had occurred before

Psychology: The illusion of having already experienced something actually being experienced for the first time.
Déjà vu (French pronunciation: [deʒa vy],(literally "already seen") is the experience of feeling sure that one has already witnessed or experienced a current situation, even though the exact circumstances of the prior encounter are uncertain and were perhaps imagined. The term was coined by a French psychic researcher, Émile Boirac (1851–1917)[1] in his book L'Avenir des sciences psychiques ("The Future of Psychic Sciences"), which expanded upon an essay he wrote while an undergraduate. The experience of déjà vu is usually accompanied by a compelling sense of familiarity, and also a sense of "eeriness", "strangeness", "weirdness", or what Sigmund Freud calls "the uncanny". The "previous" experience is most frequently attributed to a dream, although in some cases there is a firm sense that the experience has genuinely happened in the past.
The similarity between a déjà-vu-eliciting stimulus and an existing, but different, memory trace may lead to the sensation. Thus, encountering something which evokes the implicit associations of an experience or sensation that cannot be remembered may lead to déjà vu. In an effort to experimentally reproduce the sensation, Banister and Zangwill (1941) used hypnosis to give participants posthypnotic amnesia for material they had already seen. When this was later re-encountered, the restricted activation caused thereafter by the posthypnotic amnesia resulted in three of the 10 participants reporting what the authors termed "paramnesias".
Jamais vu (from French, meaning "never seen") is a term in psychology which is used to describe any familiar situation which is not recognized by the observer.
Often described as the opposite of déjà vu, jamais vu involves a sense of eeriness and the observer's impression of seeing the situation for the first time, despite rationally knowing that he or she has been in the situation before. Jamais vu is more commonly explained as when a person momentarily does not recognize a word, person, or place that they already know. Jamais vu is sometimes associated with certain types of aphasia, amnesia, and epilepsy.
[1] Émile Boirac (1851 - 1917) was a French philosopher, parapsychologist, promoter of Esperanto[2] and writer[THE PSYCHOLOGY OF THE FUTURE BY EMILE BOIRAC-1918].
Boirac was born in Guelma, Algeria. He became president of the University of Grenoble in 1898, and in 1902 president of Dijon University. A notable advocate for the universal language, Esperanto, he presided over its 1st Universal Congress (Boulogne-Sur-Mer, France, 7 August to 12 August 1905) and directed the Academy of Esperanto.

He was one of the first to use the term "déjà vu", where it appeared in a letter to the editor of "Review Philosophique" in 1876, and subsequently in Boirac's book L'Avenir des Sciences Psychiques, where he also proposed the term "metagnomy" ("knowledge of things situated beyond those we can normally know") as a more precise description for what was, then, commonly known as clairvoyance..

He was one of a group that conducted experiments on the Italian medium Eusapia Palladino. He also investigated animal magnetism, and various hypnotic phenomena such as the induction of sleep, "transposition of senses", "magnetic rapport", "exteriorisation of sensitiveness", "exteriorisation of motor nerve force" etc.

Boirac died in Dijon in 1917.
[2]Esperanto (help•info) is the most widely spoken constructed international auxiliary language. Its name derives from Doktoro Esperanto (Esperanto translates as 'one who hopes'), the pseudonym under which L. L. Zamenhof published the first book detailing Esperanto, the Unua Libro, in 1887. Zamenhof's goal was to create an easy-to-learn and politically neutral language that transcends nationality and would foster peace and international understanding between people with different regional and/or national languages.

Estimates of Esperanto speakers range from 10,000 to 2,000,000 active or fluent speakers, as well as native speakers, that is, people who learned Esperanto from their parents as one of their native languages. Esperanto is spoken in about 115 countries. Usage is particularly high in Europe, east Asia, and South America. The first World Congress of Esperanto was organized in France in 1905. Since then congresses have been held in various countries every year with the exception of years in which there were world wars. Although no country has adopted Esperanto officially, Esperanto was recommended by the French Academy of Sciences in 1921 and recognized in 1954 by UNESCO (which later, in 1985, also recommended it to its member states). In 2007 Esperanto was the 32nd language that adhered to the "Common European Framework of Reference for Languages: Learning, Teaching, Assessment (CEFR)". As of October 2011, the Esperanto Wikipedia had the 27th highest count of Wikipedia articles. Esperanto is currently the language of instruction of the International Academy of Sciences in San Marino. There is evidence that learning Esperanto may provide a superior foundation for learning languages in general, and some primary schools teach it as preparation for learning other foreign languages.