roof of fourth ventricle n.
The roof of the fourth ventricle formed by the inferior and the superior medullary vela.
- Roof of tympanum
roof of tympanum n. The roof of the middle ear, formed by the thinned anterior surface of the petrous portion of the temporal bone.
- Roof plate
roof plate or roofplate n. The thin layer of the embryonic neural tube that connects the lateral plates dorsally.
noun, Optics. 1. Amici prism. noun, Optics. 1. a compound prism that spreads out incident white light into a spectrum but produces no deviation of the central color of the dispersed beam.
noun 1. a black rat, Rattus rattus alexandrinus, often found on the upper floors of buildings in warm areas.