The story is a sort of extended short story. In a sense ( I assume you mean the familiar Scrooge ghost-tale) is in a very real sense a Problem Novel- one of the first, focusing on the personal problems of the lead character. this is not the most chummy of literary modes, unlike science-fiction and romance.
A minor story that runs inside the main story is called a sub-plot.
The plot is what actually happens: the storyline. The sequence of events in the plot is the foundation (basis) for the story to unfold and is meant to organize information and events in a logical manner.
A secondary series of events in a story can be identified as a sub-plot. This refers to a plot that is secondary in comparison to the main, overarching plot.
In part, certainly. The story of Bassanio and Portia's courtship is exclusively romantic, and the episode of the rings is clearly romantic comedy. At one time, this was considered to be the main plot of the play, but now the Shylock plot, which was formerly a subplot, is considered to have much more dramatic potential and is viewed as the main plot. Even within that subplot, there is a romantic sub-sub plot, if you will, which is the story of Lorenzo and Jessica.
A subplot serves to add depth and complexity to the main plot by introducing additional storylines or character arcs. It can help to engage readers or viewers by providing contrast, suspense, or thematic resonance to the main story. Additionally, subplots can also help to highlight different themes, perspectives, or motivations within the overall narrative.
Exposition
Memory might be a bit spotty , but this could have been a SUB PLOt in the serious Drama ( A Tree Grows In Brooklyn) The sub-plot was, hoiwver played for laughs.
A Sub-plot
I never recall any plot or even sub-plot along these lines in the Comedy- which it was The Beverly Hillbillies. Granny Clampett ( Irene Ryan) was one of the lead characters.
There should be one main plot. In a longer story or novel, you can have one or two sub-plots that run along during the story, too.
A switch subservient to the main switch, possibly on a sub-panel.
Split-plot designs and nested designs use the same idea. However, the difference is that split-plot designs are used in experimental studies while nested designs are used in observational studies. If there are two factors (e.g. A & B) and if the experimenter adopts a split-plot design due to some constraints, such as the of lack of experimental units, then factor-A ("main plot factor") levels can be applied to the main plots, and factor-B ("sub-plot factor") levels can be applied to sub plots within each main plot. This scenario is otherwise called a completely randomized design (CRD). Here, factor-B levels are nested within each level of factor A. Also, the precision for the estimation of factor B is more than that of factor A in split-plot designs. Thus, before starting the experiment, the experimenter needs to consider which factor needs more attention and then label the main factor and the sub factor. One common mistake that the experimenter makes, when using the split-plot factor, is to ignore the importance of error terms. In split-plot design, there are two errors. The F value that is calculated for factor A uses error A, and the F value that is calculated for factor B, and its interaction, uses error B.