• (a.) Of or pertaining to the prosencephalon.
Pros·en`ce·phal'ic adjective (Anat.) Of or pertaining to the prosencephalon. 
prosencephalon, prosencephalic The forebrain or anterior brain vesicle of the embryo that subdivides into telencephalon and diencephalon. From it are derived the cerebral hemispheres, olfactory lobes, corpus striatum, and various parts of the thalamus; as well, as the third and the lateral ventricles.