something that follows something else
"The sequel to his first novel was published three years later, continuing the story of the main characters."
a part added to a book or play that continues and extends it
"The movie was released as a sequel to complete the story of the original film."
The events, collectively, which follow a previously mentioned event; the aftermath.
"After the initial rescue mission, the team faced a long and difficult sequel involving months of recovery and rebuilding."
In plain English: A sequel is a movie, book, or show that continues the story of an earlier one by featuring the same characters and setting.
"The sequel to that movie was even more popular than the original."
Usage: Use sequel to describe an event that directly follows another in time or narrative order, such as a movie continuation or the consequences of an action. Avoid using it for unrelated subsequent occurrences where "follow-up" might be more appropriate.
The word "sequel" comes from the Latin verb sequī, meaning "to follow." It entered English through Middle French and originally referred to something that follows or succeeds another event.