A subseries is a smaller group of things within a larger group of things, especially in a series of numbers or events.
Subseries are useful for organizing and understanding things in a big group.
Examples:
In the series of numbers 2, 4, 6, 8, the numbers 4 and 6 make a subseries.
The rainy days in April and May form a subseries within the spring season.
She found a subseries of shells on the beach.
The subseries of funny scenes in the movie made everyone laugh.
The subseries of big waves at the beach was really scary.
The subseries of red and yellow flowers in the garden was very pretty.