from The American Heritage® Dictionary of the English Language, 4th Edition
- n. The region near or immediately within a bacterial or other cell wall, outside the plasma membrane.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. The region between the plasma membrane and the outer membrane or cell wall.
from The Century Dictionary and Cyclopedia
- n. In the Peronosporeæ, a delicate hyaline peripheral layer of protoplasm, which in the pollinodium and oögonium becomes differentiated from the granular central mass, or gonoplasm. It does not share in the conjugation. See gonoplasm.
- n. In ferns, the residuum of the dissolved tapetal walls, which forms a mucilaginous protoplasmic mass in which the spores eventually lie embedded.
peri- + plasm. Coined by Peter D. Mitchell in 1961. (Wiktionary)