hem·​era | \ ˈhemərə \
plural hemerae\ -​ə(ˌ)rē \ also hemera

Definition of hemera

1 : a stratigraphic zone comprising the time range of a particular fossil species
2 : a period of time during which a race of organisms is at the apex of its evolution

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 hemera

New Latin, from Greek hēmera day; akin to Greek ēmar day, Armenian aur

Keep scrolling for more

Learn More about hemera

Statistics for hemera

Cite this Entry

“Hemera.” The Merriam-Webster.com Dictionary, Merriam-Webster Inc., https://www.merriam-webster.com/dictionary/hemera. Accessed 9 December 2019.

Comments on hemera

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


contradictory or incongruous words

Get Word of the Day daily email!

Test Your Vocabulary

Semantic Drift Quiz

  • a twisty river
  • Which of the following was once a synonym for fun?
Spell It

Can you spell these 10 commonly misspelled words?

Add Diction

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

Love words? Need even more definitions?

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