noun
lexicon
LEK-sih-kahn/ˈleksɪkɑːn/
The vocabulary available within a language or field.
The dictionary records the language's lexicon in orderly columns of entries.

Etymology
Greek lexikon designated a word-book. The meaning expanded figuratively from a book collecting words to the vocabulary itself, including the words characteristic of a particular field, person, or text.
In context
your surface lexicon is the size that it is because you encounter those 500 to 1500 words daily
More examples
- The English lexicon includes words borrowed from many languages.
- She is still learning the lexicon of computer programming.
- Law and medicine have distinct lexicons, even when they share words.
Forms
lexicon · lexicons · lexica
lexical adjective — Relating to words and their meanings.
Similar words
- vocabulary
- A more everyday term for the same body of words.
- terminology
- Focuses on specialized terms rather than a field's entire vocabulary.
- jargon
- Emphasizes specialized language that outsiders may find difficult to understand.