Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
Rhacōtes, ae, or Rhacōtis, is, f., an ancient name of the site of Alexandria in Egypt, form Rhacotes, Plin. 5, 10, 11, § 62; form Rhacotis, Tac. H. 4, 84.