ultrastructure

noun

ul·​tra·​struc·​ture ˈəl-trə-ˌstrək-chər How to pronounce ultrastructure (audio)
: biological structure and especially fine structure (as of a cell) not visible through an ordinary microscope
ultrastructural
ˌəl-trə-ˈstrək-chə-rəl How to pronounce ultrastructure (audio)
-ˈstrək-shrəl
adjective
ultrastructurally adverb

Examples of ultrastructure in a Sentence

Recent Examples on the Web
Examples are automatically compiled from online sources to show current usage. Read More Opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback.
This process would probably be destructive because there may be no way to access the brain’s ultrastructure except by cutting it into wafer-thin slivers. — Christof Kochgiulio Tononi, IEEE Spectrum, 25 May 2017

Word History

First Known Use

1939, in the meaning defined above

Time Traveler
The first known use of ultrastructure was in 1939

Rhymes for ultrastructure

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Browse Nearby Words

ultrasound
ultrastructure
ultrathin
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Cite this Entry

“Ultrastructure.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/ultrastructure. Accessed 23 Apr. 2025.

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Medical Definition

ultrastructure

noun
ul·​tra·​struc·​ture ˈəl-trə-ˌstrək-chər How to pronounce ultrastructure (audio)
: biological structure and especially fine structure (as of a cell) not visible through a light microscope
ultrastructural
ˌəl-trə-ˈstrək-chə-rəl, -ˈstrək-shrəl How to pronounce ultrastructure (audio)
adjective
ultrastructurally
-ē How to pronounce ultrastructure (audio)
adverb
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