periplast

noun

peri·plast ˈper-ə-ˌplast

: plasma membrane

also : a proteinaceous subcellular layer below the plasma membrane especially of a euglena

Word History

First Known Use

1853, in the meaning defined above

Time Traveler

The first known use of periplast was in 1853

See more words from the same year

Browse Nearby Words

periplasmodium

periplast

periplus

See all Nearby Words

Cite this Entry

Style

“Periplast.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/periplast. Accessed 27 Nov. 2025.

Copy Citation

Medical Definition

periplast

noun

peri·plast ˈper-ə-ˌplast

: plasma membrane

More from Merriam-Webster

Word of the Day

cornucopia

Listen to the pronunciation of cornucopia

See Definitions and Examples »

Get Word of the Day daily email!

Popular in Grammar & Usage

31 Useful Rhetorical Devices

'Affect' vs. 'Effect'

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

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

What’s the difference between ‘cemetery’ and ‘graveyard’?

Popular in Wordplay

Are you in a 'food coma'?

The Words of the Week - Nov. 21

17 Words for Dog Breeds

Words That Turned 100 in 2025

How 'Namaste' Entered The English Language

Popular

31 Useful Rhetorical Devices

Are you in a 'food coma'?

The Words of the Week - Nov. 21