Merriam-Webster Logo
SINCE 1828
Menu
dictionary thesaurus

book gill

noun

Definition of book gill 

: a gill found in the horseshoe crabs that consists of membranous folds arranged like the leaves of a book

Love words?

You must — there are over 200,000 words in our free online dictionary, but you are looking for one that’s only in the Merriam-Webster Unabridged Dictionary.

Start your free trial today and get unlimited access to America's largest dictionary, with:

  • More than 250,000 words that aren't in our free dictionary
  • Expanded definitions, etymologies, and usage notes
  • Advanced search features
  • Ad free!

First Known Use of book gill

1897, in the meaning defined above

Keep scrolling for more

Learn More about book gill

Dictionary Entries near book gill

bookfair

book fell

book-fold

book gill

book hand

bookholder

bookhunter

Statistics for book gill

Look-up Popularity

Time Traveler for book gill

The first known use of book gill was in 1897

See more words from the same year

Comments on book gill

What made you want to look up book gill? Please tell us where you read or heard it (including the quote, if possible).

Show Comments  Hide Comments 

WORD OF THE DAY

linchpin

one that holds something together

Get Word of the Day daily email!

Test Your Vocabulary

Words from Greek and Roman Mythology Quiz

  • the-triumph-of-venus-by-alessandro-magnasco
  • Boreal comes from the name of the ancient Greek god of which wind?
Name That Thing

Test your visual vocabulary with our 10-question challenge!

TAKE THE QUIZ
Syn City

Test Your Knowledge - and learn some interesting things along the way.

TAKE THE QUIZ

Love words? Need even more definitions?

Subscribe to America's largest dictionary and get thousands more definitions and advanced search—ad free!

Words at Play

Ask the Editors

Word Games