Since

1. conj. Seeing that; because; considering; — formerly followed by that.
2. adv. From a definite past time until now; as, he went a month ago, and I have not seen him since.
3. adv. In the time past, counting backward from the present; before this or now; ago.
4. adv. When or that.
5. prep. From the time of; in or during the time subsequent to; subsequently to; after; — usually with a past event or time for the object.

The word meanings were obtained from OPTED(The Online Plain Text English Dictionary), which is based on “The Project Gutenberg Etext of Webster’s Unabridged Dictionary” which is in turn based on the 1913 US Webster’s Unabridged Dictionary (See Project Gutenburg), as a text file.