thorax

noun

tho·​rax ˈthȯr-ˌaks How to pronounce thorax (audio)
plural thoraxes or thoraces ˈthȯr-ə-ˌsēz How to pronounce thorax (audio)
1
: the part of the vertebrate body between the neck and the abdomen
If you count the vertebrae in the necks and thoraxes of mice and chickens, you will find that a mouse has seven neck and 13 thoracic vertebrae, a chicken 14 and seven, respectively.Matt Ridley
also : thoracic cavity
The thorax is evaluated for fluid at the flanks and for pneumothorax anteriorly. Christoper L. Moore
2
: the middle of the three chief divisions of the body of an insect
Of nearly a million described species of insects, none has a biramous appendage, and nearly all have exactly three pairs of limbs on the thorax.Stephen Jay Gould
This haunting pitch issues from drum tissue stretched over the thorax of the male annual cicada …Ted Williams
also : the corresponding part of a crustacean or an arachnid
The brown recluse spider … is brown and has fuzzy body hair and a dark violin- or pear-shaped band on the dorsum of its thorax. Peter F. Weller

Examples of thorax in a Sentence

Recent Examples on the Web The ant was shaking her thorax at him now, beckoning him closer with her pincers. Simon Rich, The New Yorker, 15 Jan. 2024 Black with black and white bristles, the species’ segmented body (including its thorax and its abdomen) is adorned in bold stripes. Sam Walters, Discover Magazine, 3 Jan. 2024 These are a set of genes that help determine which segments of an embryo will become the head, thorax, abdomen, and so on. Elizabeth Rayne, Ars Technica, 8 Dec. 2023 To keep the ants from wandering (or simply falling) off the treadmill, the scientists glued the thorax to a small pin. Seriously Science, Discover Magazine, 22 Feb. 2017 Typically, the head, thorax and legs are dark brown and the abdomen is brownish black. Natalie Neysa Alund, USA TODAY, 14 June 2023 An x-ray reveals a complete surprise to the attending physician, an anomaly wildly beyond the expectations of the typical anatomical variant: dozens of balls in the thorax. Rebecca Kreston, Discover Magazine, 24 Mar. 2017 Dickman has found that lesser hairy-footed dunnarts (Sminthopsis youngsoni) and Wongai ningaui (Ningaui ridei)—small mouselike marsupials in Australian deserts—preferentially eat the abdomens and thoraxes of their insect, spider and centipede prey. Stephanie Pappas, Scientific American, 11 Apr. 2023 Another intern taught her how to spread the jam evenly, monitor the drying process, then use tweezers to assemble the head, thorax, abdomen and wings. Julia Moskin, New York Times, 9 Jan. 2023 See More

These examples are programmatically compiled from various online sources to illustrate current usage of the word 'thorax.' Any opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback about these examples.

Word History

Etymology

Middle English, from Latin thorac-, thorax breastplate, thorax, from Greek thōrak-, thōrax

First Known Use

15th century, in the meaning defined at sense 1

Time Traveler
The first known use of thorax was in the 15th century

Dictionary Entries Near thorax

Cite this Entry

“Thorax.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/thorax. Accessed 4 Mar. 2024.

Kids Definition

thorax

noun
tho·​rax ˈthō(ə)r-ˌaks How to pronounce thorax (audio)
ˈthȯ(ə)r-
plural thoraxes or thoraces ˈthōr-ə-ˌsēz How to pronounce thorax (audio)
ˈthȯr-
1
: the part of the body of a mammal between the neck and the abdomen
also : its cavity in which the heart and lungs lie
2
: the middle of the three main divisions of the body of an insect

Medical Definition

thorax

noun
plural thoraxes or thoraces ˈthōr-ə-ˌsēz, ˈthȯr- How to pronounce thorax (audio)
1
a
: the part of the body in vertebrates that is situated between the neck and the abdomen and supported by the ribs, costal cartilages, and sternum
2
: the middle of the three chief divisions of the body of an insect
also : the corresponding part of a crustacean or an arachnid
Last Updated: - Updated example sentences
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