macronucleus

noun

mac·​ro·​nu·​cle·​us ˌma-krō-ˈnü-klē-əs How to pronounce macronucleus (audio)
-ˈnyü-
: a relatively large densely staining nucleus of most ciliate protozoans that is derived from micronuclei and controls various nonreproductive functions
macronuclear
ˌmak-rō-ˈnü-klē-ər How to pronounce macronucleus (audio)
-ˈnyü-
 nonstandard  -kyə-lər
adjective

Word History

Etymology

macro- + nucleus

First Known Use

1887, in the meaning defined above

Time Traveler
The first known use of macronucleus was in 1887

Dictionary Entries Near macronucleus

macronucleate

macronucleus

macronutrient

See More Nearby Entries 

Cite this Entry

“Macronucleus.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/macronucleus. Accessed 30 Nov. 2024.

Copy Citation

Share

Medical Definition

macronucleus

noun
mac·​ro·​nu·​cle·​us ˌmak-rō-ˈn(y)ü-klē-əs How to pronounce macronucleus (audio)
plural macronuclei -ˌī How to pronounce macronucleus (audio) also macronucleuses
: a relatively large densely staining nucleus of most ciliate protozoans that is derived from micronuclei and controls various nonreproductive functions compare micronucleus
macronuclear
ˌmak-rō-ˈn(y)ü-klē-ər How to pronounce macronucleus (audio)
adjective

More from Merriam-Webster on macronucleus

Britannica.com: Encyclopedia article about macronucleus

Love words? Need even more definitions?

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

Popular in Grammar & Usage

See All

How to Use Em Dashes (—), En Dashes (–) , and Hyphens (-)

Plural and Possessive Names: A Guide

The Difference Between 'i.e.' and 'e.g.'

Why is '-ed' sometimes pronounced at the end of a word?

What's the difference between 'fascism' and 'socialism'?
See All

Popular in Wordplay

See All

Terroir, Oenophile, & Magnum: Ten Words About Wine

8 Words for Lesser-Known Musical Instruments

10 Words from Taylor Swift Songs (Merriam's Version)

9 Superb Owl Words

15 Words That Used to Mean Something Different
See All

Games & Quizzes

See All
Play Quordle: Guess all four words in a limited number of tries. Each of your guesses must be a real 5-letter word.
Quordle Can you solve 4 words at once?
Play Blossom: Solve today's spelling word game by finding as many words as you can using just 7 letters. Longer words score more points.
Blossom Word Game Pick the best words!
Play Missing Letter: a crossword with a twist. Each of the 25 puzzle words start with a different letter of the alphabet. Which letter is missing?
Missing Letter A daily crossword with a twist
sweet smart pug puppy dog sitting in front of blackboard with chalk question marks
Commonly Confused Words Quiz Vol. 3 Do you have a (flare/flair) for choosing the righ...