turn [OE] The origin of Old English turn is Latin tornare ‘to turn’, from tornos, the Greek word for a lathe. The sense ‘a song or other short performance’ developed in the early 18th century from the meaning ‘an opportunity or obligation to do something’, as in ‘It’s your turn’, which is medieval. Card games and betting combine to give us a turn-up for the books [L19th]. Turn-up here refers to the turning up or over of a particular card in a game, while the book is one kept by a bookie to record bets made in a race. The leaf in to turn over a new leaf [M16th], is a sheet of paper in a book, not a part of a plant or tree. A turncoat is a person who deserts one party to join an opposing one. The term dates from the mid 16th century and is said to be a reference to a Duke of Saxony whose land was located between the French and Saxons, who were at war with each other. The Duke wore a reversible coat, one side of which was blue (the Saxon colour) and the other side white (the French colour), so that he could change his display of allegiance quickly should the need arise. However, many similar stories are told of other people at other times.