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mesosome

noun

me·​so·​some ˈme-zə-ˌsōm How to pronounce mesosome (audio)
ˈmē-
-sə-
: an organelle of bacteria that appears as an invagination of the plasma membrane and functions either in DNA replication and cell division or excretion of exoenzymes

Word History

First Known Use

1960, in the meaning defined above

Time Traveler
The first known use of mesosome was in 1960

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Cite this Entry

“Mesosome.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/mesosome. Accessed 30 Nov. 2025.

Medical Definition

mesosome

noun
: an organelle of bacteria that appears in electron micrographs as an invagination of the plasma membrane and is a site of localization of respiratory enzymes
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