since

1 since /ˈsɪns/ preposition
1 since
/ˈsɪns/
preposition
Britannica Dictionary definition of SINCE
: in the time after (a specified time or event in the past) : from (a point in the past) until the present time

since the year one

— see year

since when?

— used to show that you are surprised and often angry, annoyed, or doubtful about what someone has said or done
2 since /ˈsɪns/ conjunction
2 since
/ˈsɪns/
conjunction
Britannica Dictionary definition of SINCE
1 
: in the period after the time when
2 
: from the time in the past when
3 
— used to introduce a statement that explains the reason for another statement
3 since /ˈsɪns/ adverb
3 since
/ˈsɪns/
adverb
Britannica Dictionary definition of SINCE
1 
: from a past time until now
2 
: after a time in the past
3 
: before the present time
— see also long since at 2long