'System' in the Bible

but had against him certain questions of their own system of worship, and concerning a certain Jesus who is dead, whom Paul affirmed to be living.

But thanks be to God that though you were once in thraldom to Sin, you have now yielded a hearty obedience to that system of truth in which you have been instructed.

So also we [whether Jews or Gentiles], when we were children (spiritually immature), were kept like slaves under the elementary [man-made religious or philosophical] teachings of the world.