adverb

1. For the reason (that).

2. On account (of), for sake (of).

   “My life is ruined because of you!”

3. (by ellipsis) 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".

preposition

1. On account of, because of.

conjunction

1. By or for the cause that; on this account that; for the reason that.

   “I hid myself because I was afraid.”

2. As is known, inferred, or determined from the fact that.

   “I don't think he is a nice person, because he yells at people for no reason.”

3. So that, in order that.

Synonyms: as, for, for sake, for that, forthy, forwhy, inasmuch as, since