peri·​plasm ˈper-ə-ˌpla-zəm How to pronounce periplasm (audio)
: the region in a gram-negative bacterium between the plasma membrane and an outer surrounding membrane that contains especially enzymes and a thin layer of peptidoglycan
periplasmic adjective

Word History

First Known Use

1961, in the meaning defined above

Time Traveler
The first known use of periplasm was in 1961

Dictionary Entries Near periplasm

Cite this Entry

“Periplasm.” Dictionary, Merriam-Webster, Accessed 2 Feb. 2023.

Love words? Need even more definitions?

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

Challenging Words You Should Know

  • hedgehog reading a book
  • Often used to describe “the march of time,” what does inexorable mean?
How Strong Is Your Vocabulary?

Test your vocabulary with our 10-question quiz!

Solve today's spelling word game by finding as many words as you can with using just 7 letters. Longer words score more points.

Can you make 12 words with 7 letters?