The earliest known English-language work on magic, or what was then known as legerdemain (sleight of hand), was published anonymously in 1635 under the title Hocus Pocus Junior: The Anatomie of Legerdemain. Further research suggests that "Hocus Pocus" was the stage name of a well known magician of the era. This may be William Vincent, who is recorded as having been granted a license to perform magic in England in 1619. Whether he was the author of the book is unknown.
The origins of the term remain obscure. The most popular conjecture is that it is a garbled Latin religious phrase or some form of ‘dog’ Latin. Some have associated it with similar-sounding fictional, mythical, or legendary names. Others dismiss it as merely a combination of nonsense words.
In some Slavic languages, "pokus" means an "attempt" or an "experiment", as for example in Czech or Slovak language. The word is derived from the Protoslavic word "kusiti", which is itself derived from Gothic "kausajn" meaning "to try", "to attempt". This may indicate that the wording belongs to the alchemy kitchen and court of Rudolf II, Holy Roman Emperor (1552 – 1612). Also, hocus may mean "to cheat" in Latin or a distorted form of the word hoc, "this". Combination of the two words may give a sense, especially both meanings together "this attempt/experiment" and "cheated attempt/experiment".
Some believe it originates from a corruption or parody of the Catholic liturgy of the Eucharist, which contains the phrase “Hoc est enim corpus meum”, meaning This is my body. This explanation goes back to speculations by the Anglican prelate John Tillotson, who wrote in 1694: