Pronunciation: (thôr'aks, thōr'-),[key] —n., —pl.tho•rax•es, tho•ra•cesPronunciation: (thôr'u-sēz", thōr'-).[key] 1. Anat.the part of the trunk in humans and higher vertebrates between the neck and the abdomen, containing the cavity, enclosed by the ribs, sternum, and certain vertebrae, in which the heart, lungs, etc., are situated; chest.
2. Zool.a corresponding part in other animals.
3. (in insects) the portion of the body between the head and the abdomen. See diag. under insect.