Orthoceras

noun
Or·​thoc·​er·​as | \ ȯ(r)ˈthäsərəs \

Definition of Orthoceras

: an ill-defined genus of extinct nautiloid cephalopod mollusks having a long tapering shell that is nearly or quite straight, almost smooth, and many-chambered

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!

History and Etymology for Orthoceras

New Latin, from orth- + -ceras

Keep scrolling for more

Learn More about Orthoceras

Statistics for Orthoceras

Cite this Entry

“Orthoceras.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/Orthoceras. Accessed 20 Jan. 2021.

Comments on Orthoceras

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

WORD OF THE DAY

Test Your Vocabulary

Words of Snow and Ice Quiz

  • image1037863653
  • Which of the following refers to thin, bending ice, or to the act of running over such ice?
True or False

Test your knowledge - and maybe learn something along the way.

TAKE THE QUIZ
Typeshift

Anagram puzzles meet word search.

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!