What Is Vocabulary?

The noun vocabulary (or “vocab” for short) refers to the words used in a language.

“Vocabulary” can have at least three different meanings:

  1. all of the words in a language
    New words are constantly being added to the vocabulary of English.
  2. the words used in a particular context
    If you want to do an MBA you need to improve your business vocabulary.
    My neighbour is a doctor so he has an extensive medical vocabulary.
    I’ve just bought a book on the vocabulary of slang.
  3. the words an individual person knows
    The teacher said that my vocabulary is good.

(English Club)