Secchi disc

Sec·​chi disc | \ ˈsekē- \

Definition of Secchi disc

: a reflective disc lowered into a body of water to permit measurement of the relative transparency of the water by recording the depth at which the disc is no longer visible

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 Secchi disc

after Angelo Secchi †1878 Italian astronomer

Keep scrolling for more

Learn More about Secchi disc

Statistics for Secchi disc

Cite this Entry

“Secchi disc.” Dictionary, Merriam-Webster, Accessed 12 Aug. 2020.

Comments on Secchi disc

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


Test Your Vocabulary

Original Meanings Quiz

  • rembrandt painting a young scholar and his tutor
  • Which of the following is the earliest known sense of the word awe?
Spell It

Can you spell these 10 commonly misspelled words?


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!