corpus cal·lo·sum 
(kə-lōsəm)
(kə-lōsəm)n. pl. corpora cal·lo·sa (kə-lōsə)
The arched bridge of nervous tissue that connects the two cerebral hemispheres, allowing communication between the right and left sides of the brain.
[New Latin corpus callōsum : Latin corpus, body + Latin callōsum, neuter of callōsus, callous.]