since: [15] Since is a contracted form of Middle English sithenes ‘since’. This in turn went back (with the addition of a final -s) to Old English siththan, a compound adverb and conjunction formed from sīth ‘after’ (a relative of German seit ‘since’) and thām ‘that’.
since (adv.)
early 15c., synnes, from sithenes "since," from sithen (plus adverbial genitive -es), from Old English sieean "afterward, from now on, hereafter, further, later, as soon as, after that," originally sie ean "after that," from sie "after" (see sith) + ean, weakened form of eam, dative of e?t (see that).
As a conjunction from late 14c.; as a preposition from 1510s; "from the time when," hence "as a consequence of the fact that." Modern spelling replaced syns, synnes 16c. to indicate voiceless final -s- sound. Since when? often expressing incredulity, is from 1907.
例文
1. Since the birds interbreed they cannot be classed assed as different species.
これらの鳥は交雑繁殖を行うため、異なる種に分類することはできません。
2.I 've had the hots for him ever since he came to college.
彼が大学に来てから、私は彼に対して春の心が芽生えた。
3."Prices are down 40 per cent since Christmas，"he lamented.
「クリスマス以来物価が4割下がった」と悲嘆した。
4.The mechanics of the job，however，have changed little since then.
しかし、ワークフローはそれ以来ほとんど変化していない。
5.Rock 'n 'roll has become so commercialised and safe since punk.