Recorded as Nanson and very occasionally as the dialectal Nansom, this is an English surname. It is a metronymic, which is to say that it descends from a mothers name not the father. This is not as rare an occurence as may be supposed, with some very popular surnames such as Marriott meaning "The son of Mary", deriving from the similar source. In this case the origination is from the baptismal name Ann, through the nickname "Nan", although the French medieval spellings of Nanon and Nanette may also be a source. It is said that during the Middle Ages Nan was such a popular short form that even people christened Ann were always referred as Nan. This included Ann Boleyn, however after her unfortunate "reign" the name fell into disrepute, and has never regained its popularity. To add further fuel to the fire a "nanny house" was a bordello in the 17th century, and in the ballad of "The two women of Abingdon" one of the women called Nan was described as "wanton"! The name was then changed again to Nancy, a form which has remained popular ever since. The earliest known recording is that of Robert Nanson in the Poll Tax Rolls of Yorkshire in 1379.