The definition of semipermeable is capable of only having certain things get through it.
An example of semipermeable is a selectively permeable membrane.
allowing some substances to pass; permeable to smaller molecules but not to larger ones, as a membrane in osmosis
- Partially permeable.
- Allowing passage of certain, especially small, molecules or ions but acting as a barrier to others. Used of biological and synthetic membranes.
(comparative more semipermeable, superlative most semipermeable)
- Permeable to some things and not to others, as a cell membrane which allows some molecules through but blocks others substances.