Seanchus.—From the old Celtic root sen, old, which has direct cognates, not merely in the Indo-European, but also in the Semitic; Arabic, sen, old, ancient—sunnah, institution, regulation; Persian, san, law, right; sanna, Phoenicibus idem fuit quod Arabibus summa, lex, doctrina jux canonicum.—Bochart, Geo. Sæ. 1. ii. c. 17. See Petrie's Tara, p. 79.
Day.—O'Curry, page 201.
Works.—He appears to have been the author of the original Book of Rights, and "commenced and composed the Psalter of Caiseal, in which are described the acts, laws," &c.—See Preface to Seanchus Mor, p. 17.