Since

Adverb

1. From a specified time in the past.

Preposition

1. 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.
   1. Continuously during that period of time.
   2. At certain points during that period of time.

Antonyms

• until

Conjunction

1. From the time that.
2. Because.
3. (obsolete) When or that.

Synonyms

• (from the time that): sithen (obsolete); see also Thesaurus:since
• (because): sith (obsolete); see also Thesaurus:because