[ sem-ee-pur-mee-uh-buh l, sem-ahy- ]
/ ˌsɛm iˈpɜr mi ə bəl, ˌsɛm aɪ- /


permeable only to certain small molecules: a semipermeable membrane.

Origin of semipermeable

First recorded in 1895–1900; semi- + permeable

Related forms

sem·i·per·me·a·bil·i·ty, noun Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

Examples from the Web for semi-permeable

  • The term "osmotic membrane" should therefore in all cases replace that of "semi-permeable membrane."

    The Mechanism of Life|Stphane Leduc

British Dictionary definitions for semi-permeable


/ (ˌsɛmɪˈpɜːmɪəbəl) /


(esp of a cell membrane) selectively permeable

Derived Forms

semipermeability, noun
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

Medicine definitions for semi-permeable


[ sĕm′ē-pûrmē-ə-bəl, sĕm′ī- ]


Partially permeable.
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.