since
(adverb, conjunction, preposition)
adverb
1. From a specified time in the past.
- I had seen him previously, but hadn't seen him since.
conjunction
1. From the time that.
- I have loved you since I first met you.
2. Because.
3. (obsolete) When or that.
preposition
1. From (time).
- I have known her since last year.