Merriam-Webster Online Dictionary
because (conjunction)1.
for the reason that - since rested because he was tired
2.
the fact that - that the reason I haven't been fired is because my boss hasn't got round to it yet E. B. White
Merriam-Webster Online Thesaurus
because (conjunction)for the reason that
SYNONIMS:
as, as long as, because, being (as as how that), 'cause, considering, for, inasmuch as, now, seeing, whereas