third ventricle: a narrow ventricle in the midplane below the corpus callosum; communicates with the fourth ventricle via the Sylvian aqueduct
ventricle: one of four connected cavities in the brain; is continuous with the central canal of the spinal cord and contains cerebrospinal fluid
caber: a heavy wooden pole (such as the trunk of a young fir) that is tossed as a test of strength (in the Highlands of northern Scotland)