subset

Short definition from Wiktionary

Noun

1. 1
   A set A such that every element of A is also an element of S.
2. 2
   A group of things or people, all of which are in a specified larger group.

Verb

1. 1
   To take a subset of.
2. 2
   To extract only the portions of (a font) that are needed to display a particular document.