The word lieutenant derives from French; the lieu meaning "place" as in a position; and tenant meaning "holding" as in "holding a position"; thus a "lieutenant" is somebody who holds a position in the absence of his superior. The English pronunciation was prevalent during the 14th and 15th centuries with the word being variously spelled as lieftenant, lyeftenant or luftenant. It may have originated from a mistaken reading of the 'u' as a 'v' (u and v originally were written as the same letter), with v eventually assimilating in voice to /f/. Some sources state that the original French word lieu had an alternative form spelt and pronounced lieuf, and that the modern standard English form retains the former spelling and the latter pronunciation. It has also been speculated that it may have come from a fanciful etymology which associated it with the verb 'to leave', as the lieutenant only took up his duties once his superior officer had 'left'. Another theory comes from the fact that in typical propriety the person or persons standing to the rear-left of a gentleman held power and were typically those directly second to him. The person or persons standing to the rear-right were considered to have no or less standing than those to the rear-left, such as aides, bodyguards, wives, etc., often holding this position for simple facility rather than societal importance. This tradition remains in military parades, with lieutenants standing to the rear-left of the commanding officer (when facing the advance.) http://en.wikipedia.org/wiki/Lieutenant