Subsequence

The subsequence of odd numbers in the sequence of natural numbers.

The subsequence of consonants in the word "banana".

The months of the year are a subsequence of the larger concept of the passage of time.

The subsequence of shots in the movie that won the Oscar for Best Cinematography was the tracking shot in the opening scene, the crane shot over the city, and the close-up of the protagonist's face.

The subsequence of books in a library that are about the American Revolution is a proper subset of all the books in the library.