[sem-ee-pur-mee-uh-buh l, sem-ahy-]
permeable only to certain small molecules: a semipermeable membrane.
Origin of semipermeable
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019
(esp of a cell membrane) selectively permeable
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012
Allowing passage of certain, especially small, molecules or ions but acting as a barrier to others. Used of biological and synthetic membranes.
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.