Enter a clue or pattern or both:
The Clue
Wordbooks; calepins (8 letter answer)
The Answer
LEXICONS
Tags
Notes
The answer LEXICONS is so rare that it appears less than once every 2500 puzzles.
Definition
LEXICON as a noun:
1. (vocabulary, lexicon, mental lexicon) = a language user's knowledge of words
2. (dictionary, lexicon) = a reference book containing an alphabetical list of words with information about them