From 'Cambridge Street Names -Their Origins And Associations' by Ronald Gray and Derek Stubbings, 2010:
The only street-name in Cambridge that has connections with prehistoric times is ARBURY Road. The name is spelled Herburg, Ertburg and similar in thirteenth-century documents, and means earthwork. It used to be thought that Arbury Camp, at the north end of the road, was a fort like the one at Wandlebury or the War Ditches at LIME KILN Hill, south of the reservoir (now destroyed) but it is today regarded as an undefended site. A low circular bank and ditch about 100 metres in diameter, it was almost certainly an iron age enclosure for keeping animals safe from wolves and robbers. (See Alison Taylor: 'Prehistoric Cambridgeshire', 1977, and Sallie Purkis, 'Arbury Is Where We Live!', EARO, The Resource Centre, Back Hill, Ely, 1981.)
The book is highly recommended for anybody interested in Cambridge history.