Emily Dickinson Lexicon

SINCE, prep. [or adv. Sw. sedan; Dan. siden; D. sint; supposed to be contracted from Sax. siththan, which is from sithian, to pass, to go; and siththan may be the participle, and denote past, gone, and hence after, afterward. Sith in Saxon, has a like sense. Our early writers used sith, sithen, sithence; the latter is evidently a corruption of siththan. It may be doubted whether Sw. sen, Dan. seen, slow, late, is a contraction of this word; more probably it is not.]

1. After; from the time that. The proper signification of since is after, and its appropriate sense includes the whole period between an event and the present time. I have not seen my brother since January. The Lord hath blessed thee, since my coming. – Gen. xxx. Holy prophets, who have been since the world began. – Luke i. John ix. Since then denotes, during the whole time after an event; or at any particular time during that period.
2. Ago; past; before this. “About two years since, an event happened,” that is, two years having passed.
3. Because that; this being the fact that. Since truth and constancy are vain, / Since neither love nor sense of pain / Nor force of reason can persuade, / Then let example be obey'd. – Glanville. Since, when it precedes a noun, is called a preposition, but when it precedes a sentence it is called an adverb. The truth is, the character of the word is the same in both cases. It is probably an obsolete participle, and according to the usual classification of words, may be properly ranked with the prepositions. In strictness, the last clause of the passage above cited is the case absolute. “The Lord hath blessed thee, since my coming,” that is, my arrival being past. So, since the world began, is strictly, past the world began, the beginning of the world being past. In the first case, since, considered as a preposition, has coming, a noun, for its object, and in the latter case, the clause of a sentence. So we say, against your arrival, or against you come.