Definition of "subplot"

Subplot, a story line enclosed within the principal story to provide relief from the main plot's tension, add character dimension, etc.

1978, R.B. Lee & R. Misiorowski, Script Models: A Handbook for the Media Writer

Structurally, the two most variant scenes (outside of Scene ii) are Scenes 3 and 4 in which the compiler works out the variant subplot.

1998, Stephen Roy Miller, The Taming of a Shrew: the 1594 quarto

In a sense, Superman's romance with Lois Lane was a subplot and [...]

2001, Dennis O'Neil, The DC Comics Guide to Writing Comics

But this story has a subplot — a subplot about fairness and how people have divergent levels of access to knowledge and resources.

2001, Nancy Arbuthnot Johnson, Vic Neufield, Forging Links for Health Research

[...] on sixteen 8/10-acre plots (12.8 acres) well distributed over the area. [...] A 1/160-acre subplot was established in a randomly chosen corner of each [...]

1996, The American Midland Naturalist, the University of Notre Dame

There are 72 trees in each plot (6x12) and 36 trees in each subplot.

1999, E. K. Sadanandan Nambiar, Christian Cossalter, Site Management and Productivity in Tropical Plantation Forest

Hardwood and shrub stems (besides gallberry) were counted by species and measured for total height (if greater than 2 ft) on 3 strip plots per subplot that were 0.01 acre […]

2002, M. Boya Edwards, Proceedings for the Eight Biennial Southern Silvicultural Research Conference

In the pictures of places, too, an author uses economy; and for his plot, complicated and subplotted as it may seem, he cannot count on having vast stretches of eternity in which to elaborate forever.

1965, Percival Hunt, The Gift of the Unicorn: Essays on Writing, page 70