the GNU version of the Collaborative International Dictionary of English
adj. Capable of flowing or spreading in all directions; that may be diffused.
adj. Capable of passing through animal membranes by osmosis.
The Century Dictionary and Cyclopedia
Capable of diffusing, as a fluid; diffusive.
Word Usage
"Beadle and Ephrussi designed at Caltech a set of experiments, involving transplantation of larval imaginal eye discs, to study the vermilion-plus hormone, as they called the diffusible substance."