See Matthew 15:14-15 as an example; it could be a story or just a proverb -- the use varies.
A Parable is a narrative constructed for conveying an important spiritual truth.
A parable is possible -- a fable is not possible (see Judges 9:8-15 and 2 Kings 14:9).
Use of parables by Christ.
Rules for interpreting parables.
Determine the scope of teaching, seize that one central truth, make all details fit to that truth.
No conclusion should be gathered from any part of the parable.
Parables should not be made the first source or the sole source of doctrine.