noun (plural raphae pronunc. same ) Anatomy & Biology
a groove, ridge, or seam in an organ or tissue, typically marking the line where two halves fused in the embryo, in particular. the connecting ridge between the two halves of the medulla oblongata or the tegmentum of the midbrain. Botany a longitudinal ridge on the side of certain ovules or seeds. Botany a longitudinal groove in the valve of many diatoms.