What does thorax mean?
Thorax is the anatomical term for the chest, the part of the body between the neck and abdomen. In humans, it encloses the heart and lungs and is bounded below by the diaphragm. In insects and other arthropods, the word instead refers to the middle section of the body, between the head and abdomen; this section supports the legs and, in many insects, the wings. The term is consequently common in medicine, comparative anatomy, and biology, where precision is important, while chest is generally more suitable in everyday speech. Knowing thorax also reveals a broad pattern in scientific vocabulary: the same word can describe a region in vertebrate anatomy and a specialized body division in insects. Its Greek origin reflects an ancient association with protective coverings, a fitting background for a part of the body that contains vital organs and supports movement.
nounThe thorax is the part of the body between the neck and abdomen, containing the heart and lungs in humans and other vertebrates. In arthropods such as insects, it is the middle segment of the body, bearing the legs and, in many insects, the wings.
- The chest or upper part of the trunk in humans and other vertebrates.
- The middle segment of an arthropod's body, especially an insect's, bearing the legs and usually the wings.
"The surgeon examined the patient's thorax for signs of injury."
"The thorax of the beetle is covered by a hard outer shell."
"In anatomy, the thorax is separated from the abdomen by the diaphragm."
The standard plural is thoraces; thoraxes is also widely accepted.
"The museum displays the thoraces of several large insects."
In an insect, the thorax is a three-part powerhouse: it carries six legs and, often, a pair of wings.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Where does thorax come from?
The word comes through Latin from Greek thōrax, meaning chest or breastplate. Greek thōrax was also used for armor or a breastplate, an image that contributed to the word's medical sense of the chest as a protected part of the body. Related English forms such as thoracic and thoracotomy preserve the same Greek root.
How thorax is actually used
Thorax is a formal anatomical term, especially common in medicine, biology, and entomology. In everyday use, chest is more natural, while thorax is preferred when a precise anatomical or comparative context matters.
Easily confused with thorax
Thorax usually refers specifically to the chest region, whereas torso commonly means the entire trunk, including the chest, abdomen, and sometimes the pelvis.