black shale


Definition of black shale

: a dark form of shale characterized by a relatively high degree of carboniferous compounds The studies of others indicate that major phosphorite deposits are often associated with black shales and accumulated during only a few epochs of geologic history.— D. Z. Pipe et al., Science, 4 Apr. 1975

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 black shale

1730, in the meaning defined above

Keep scrolling for more

Learn More about black shale

Statistics for black shale

Look-up Popularity

Time Traveler for black shale

The first known use of black shale was in 1730

See more words from the same year

Comments on black shale

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


marked by a state of overwhelming emotion

Get Word of the Day daily email!

Test Your Vocabulary

Words from Greek and Latin Quiz

  • roman forum
  • Which of the following months comes from a Latin word for “ten”?
Name That Thing

Test your visual vocabulary with our 10-question challenge!

Bee Cubed

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!