Derailleur gears operates the lever while pedalling, the change in cable tension moves the chain-guide from side to side, "derailing" the chain onto different sprockets. For more information about the choice of particular gear ratios and sprocket sizes, see Bicycle gearing. "Derailleur" is a French word, spelled "dérailleur" in French, derived from the derailment of a train from its tracks. Its first recorded use was 1930. At least one notable bicycle industry author has attempted to promote the anglicized spelling of "derailer". As of 2013, however, neither Merriam-Webster nor the Oxford English Dictionary has an entry for "derailer". Various derailleur systems were
A Dictionary of the English Language all words which we use in the English tung...into one dictionary..." In 1598 an Italian–English dictionary by John Florio was published. It was the first English dictionary to use quotations ("illustrations") to give meaning to the word; in none of these dictionaries so far were there any actual definitions of words. This was to change, to a small extent, in schoolmaster Robert Cawdrey's "Table Alphabeticall", published in 1604. Though it contained only 2,449 words, and no word beginning with the letters "W", "X", or "Y", this was the first monolingual English dictionary. Several more dictionaries followed: in Latin, English, French