Ó Sionacháin
Ó SIONACHÁIN—I—O Shinnaghan, Shinnahan, Fox; 'descendant of Seanachán'; a variant of Ó Seanacháin, which see; the name of a Westmeath or Cavan family; sometimes incorrectly anglicised Fox, as if from 'sionnach,' a fox.
Alphabetical Index to Irish Surnames