Attested:  Pliny  Ricina (or Rignea, Riginea, Ricnea, Rhikina)   Ptolemy 2,2,11  Ρικινα; (or Εγγαρικεννα);
  Ravenna Cosmography Regaina listed at 277 among islands ‘in the western ocean’.
  Adomnan Rechru & Rechrea insula c AD700;     Tigernach Annals Rechrann

WhereRathlin Island, off Northern Ireland, at NR330079.

Name Origin:  Welsh rhygnu ‘to saw, to cut into pieces’ (favoured by Celtic scholars, as possibly conveying a sense of ‘notched’) appears not previously to have been linked with Greek ρηγνυμι ‘to break asunder’ (previously suggested here in the sense of shipwreck), but presumably they both descend from PIE *wreg- ‘to break’.  Hence perhaps an overall meaning of ‘broken part’.  Εγγα meant ‘near’.

Notes:  This analysis owes a lot to the original date of about AD 400 for the Irish name versions suggested by McCarthy (2001) where Rechrann apparently ends in rann ‘part’.  However, if Ptolemy's spelling was a typical 2-element name, with first part like ρεω ‘to flow’ and second like κινεω ‘to set in motion’, that might refer to the strong tidal streams around Rathlin Island, where a remarkable number of ships have been wrecked.  An alternative meaning based on PIE *reig- ‘to reach, to stretch out’ is also possible, and actively favoured for Ρεριγονιον at the Rhins of Galloway, but the etymology there is confused by frigid and ρικηνεις ‘shrivelled with cold’.

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Last edited: 13 August 2019