A literary genre.
Parables are brief fictional folk stories that embody easily grasped ideas, usually dealing with some aspect of the Kingdom of God. Even though a parable usually exhibits a single main theme, it is not unusual for additional ideas to be part of the total meaning.
The narrative ingredients are homespun realism, simplicity of action, suspense, foils (heightened contrasts), repetition (including threefold repetition), end stress, universal character types, and archetypes. Many include an element of unreality or exaggeration--a "crack" in the dominant realism that teases us into exploring what the stories communicate beyond the simple surface.
Parables were intended to be allegories or symbolic stories. "Parable" is derived from "to throw alongside," implying a double meaning. The simplicity propels us to see a spiritual level of meaning. Many parable details carry traditional symbolic meanings (God as father, God as owner of a vineyard, the seed as God's word, etc). Unrealistic elements signal a deeper level of meaning. The religious purpose of parables emerges only when we attach second meanings to the details - when we understand the seed that is sown is the gospel and the types of soils are various human responses. Jesus interpreted two of His parables in Matthew 13:18-23, 36-43, and attached a corresponding allegorical meaning to virtually every detail in the stories.
(The Origin of the Bible: Newly Updated by F. F. Bruce, J. I. Packer, Philip W. Comfort, and Carl F. H. Henry, 2020. The Bible as Literature by Leland Ryken, Page 135-136)
Interpretation
Interact with the story as a literal story, exploring the narrative ingredients of setting, character, and plot. Then identify the allegorical or symbolic meanings of details that stand for something else. On this basis, it is possible to state the themes or ideas implicit in the parable. Finally, apply the lesson.
(The Origin of the Bible: Newly Updated by F. F. Bruce, J. I. Packer, Philip W. Comfort, and Carl F. H. Henry, 2020. The Bible as Literature by Leland Ryken, Page 136)