noun plural
In·​sec·​ta | \ in-ˈsek-tə How to pronounce Insecta (audio) \

Medical Definition of Insecta

: a class of Arthropoda comprising segmented animals that as adults have a well-defined head bearing a single pair of antennae, three pairs of mouthparts, and usually a pair of compound eyes, a 3-segmented thorax each segment of which bears a pair of legs ventrally with the second and third often bearing also a pair of wings, and an abdomen usually of 7 to 10 visible segments without true jointed legs but often with the last segments modified or fitted with specialized extensions (as claspers, stingers, or ovipositors), that breathe air usually through a ramifying system of tracheae which open externally through spiracles or gills, that exhibit a variety of life cycles often involving complex metamorphosis, and that include the greater part of all living and extinct animals

Other Words from Insecta

insectan \ -​tən How to pronounce insectan (audio) \ adjective

Learn More about Insecta

Cite this Entry

“Insecta.” Medical Dictionary, Merriam-Webster, Accessed 12 Aug. 2020.

Comments on Insecta

What made you want to look up Insecta? Please tell us where you read or heard it (including the quote, if possible).


Test Your Vocabulary

Original Meanings Quiz

  • rembrandt painting a young scholar and his tutor
  • Which of the following is the earliest known sense of the word awe?
Spell It

Can you spell these 10 commonly misspelled words?


Test Your Knowledge - and learn some interesting things along the way.

Love words? Need even more definitions?

Subscribe to America's largest dictionary and get thousands more definitions and advanced search—ad free!