The term 'CENTRAL PART OF AN EAR' can be solved by the three-letter word COB. COB stands for the 'cone of the basilar membrane, ' which is a structure located in the cochlea of the inner ear. The cone of the basilar membrane is responsible for detecting sound vibrations and transmitting them to the auditory nerve. It is an important part of the auditory system, as it helps to convert sound waves into electrical signals that can be interpreted by the brain.