Isis, the name given to the Thames at Oxford - `An artificial formation from `Tamise' ... supposed to be a combination of `Thame' (the name of one of the headstreams of the Thames) and a hypothetical `Ise' ... E. Ekwall, Concise Oxford dictionary of English place-names (4th edn., Oxford, 1960), 266, where Higden c. 1350 is cited as the earliest example