noun
: a somewhat rhomboidal ventricle of the posterior part of the brain that connects at the front with the third ventricle through the aqueduct of Sylvius and at the back with the central canal of the spinal cord
noun
: a somewhat rhomboidal ventricle of the posterior part of the brain that connects at the front with the third ventricle through the aqueduct of Sylvius and at the back with the central canal of the spinal cord
Webster's New International English Dictionary. Новый международный словарь английского языка Webster. 2012