The phrase "central cavity" refers to a hollow space or area at the center of something. It can be thought of as a hole or empty space located in the middle of an object. Full definition
In addition to being a dental cleaning tool, the ball can hold some treats within the central cavity so it can turn into an IQ toy in no time. (geekwrapped.com)
The binding of a peptide aldehyde inhibitor marks the active site in the central cavity at the amino termini of the beta subunits and suggests a novel proteolytic mechanism. (science.sciencemag.org)
«Patients are given localized antibacterial and pain - numbing agents, and then a very fine needle is passed through the white of the eye into the central cavity where the drug is injected. (sciencedaily.com)