semi-permeable Applied to a barrier, usually a membrane, whose structure allows the passage of the solvent but prevents the passage of the solute. Compare DIFFERENTIALLY PERMEABLE MEMBRANE; SELECTIVELY PERMEABLE MEMBRANE.

semi-permeable Applied to a membrane whose structure allows the passage of only solvent molecules. A membrane that allows the passage of small molecules but prevents the passage of larger ones is called ‘differentially permeable’. The Institute of Biology recommends that biological membranes be described as ‘partially permeable’.

semi-permeable Applied to a membrane whose structure allows the passage only of solvent molecules. A membrane that allows the passage of small molecules but prevents the passage of larger ones is called ‘differentially permeable’. The Institute of Biology recommends that biological membranes be described as ‘partially permeable’.