Since (adverb)
From a specified time in the past.
“I met him last year, but haven’t seen him since.”
Since (preposition)
From: referring to a period of time ending in the present and defining it by the point in time at which it started, or the period in which its starting point occurred.
Since (preposition)
Continuously during that period of time.
“I have known her since last year.”
Because (adverb)
For the reason that.
Because (adverb)
On account of, for sake of.
“My life is ruined because of you!”
Because (adverb)
Used alone to refuse to provide a full answer a question begun with “why”, usually taken as an anapodoton of the elided full phrase “Because I said so”.
Because (conjunction)
By or for the cause that; on this account that; for the reason that.
“I hid myself because I was afraid.”
Because (conjunction)
As is known, inferred, or determined from the fact that.
“It must be broken, because I pressed the button and nothing happened.”
“He’s not a nice guy, because he yells at people for no reason.”
Because (conjunction)
So that, in order that. 15th-17th c.
Because (preposition)
On account of, because of. since at least the 20th century
“I went to the store because hungry.”