syne I. \(|)sīn\adverb Etymology: Middle English (northern dialect) syne, seyne, probably from Old Norse sīthan, from sīth since — more at since 1.chiefly Scotland: next, then 2.chiefly Scotland: later 3.chiefly Scotland: since then : ago < got a shot at me two days syne — John Buchan > II. conjunction Etymology: Middle English (northern dialect) syne, seyne, from syne, seyne, adverb Scotland: since III. preposition Etymology:syne (I) Scotland: since