In medicine that's hoe-MON-i-muss (the last u is more properly a schwa). It's used to describe a defect in the field of vision that is on the same side in both eyes, as in "right homonymous hemi-anopsia," meaning anything to the right of the midline (that is, the right half of the visual field) will not be perceived, by either eye. It might have been the central/nasal halves, or maybe the outside/lateral halves, instead. Such differences help locate pathology in the brain, i.e. tumors or localized strokes.