What does arthropod mean?
An arthropod is any member of Arthropoda, the largest phylum in the animal kingdom — a group that includes insects, spiders and other arachnids, crustaceans such as crabs and shrimp, and myriapods such as centipedes and millipedes. What unites them is a distinctive body plan: a segmented body, a tough external skeleton called an exoskeleton that must be shed as the animal grows, and paired limbs built from hinged segments. The word comes from the Greek roots 'arthron', meaning joint, and 'pous' or 'podos', meaning foot, so it literally means 'jointed foot'. Used mainly in scientific, educational, and nature-writing contexts, the term is precise rather than colloquial. Its importance is hard to overstate: arthropods account for the vast majority of known animal species and play essential roles as pollinators, decomposers, and prey within nearly every ecosystem on Earth.
nounAn invertebrate animal of the phylum Arthropoda, characterized by a segmented body, a jointed exoskeleton, and paired jointed limbs; the group includes insects, arachnids, crustaceans, and myriapods.
- An invertebrate animal belonging to the phylum Arthropoda, having a segmented body, an external skeleton, and paired jointed appendages.
"The crab scuttling across the tide pool is an arthropod, its armored body divided into distinct segments."
"Bees, spiders, and lobsters may look wildly different, but each is an arthropod."
"The fossil record shows that arthropods were among the first animals to colonize land."
Regular plural formed by adding -s. In scientific writing the capitalized 'Arthropoda' denotes the phylum itself, while lowercase 'arthropods' refers to individual animals or members generally.
"Scientists have described well over a million species of arthropods, most of them insects."
Four out of every five known animal species on Earth is an arthropod — if you lined up every described animal, roughly 80% would be one of these joint-legged survivors.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of arthropod
The word arthropod was coined in the 19th century from Modern Latin 'Arthropoda', itself built on two Ancient Greek roots: 'arthron' meaning joint, and 'pous' (stem 'podos') meaning foot. It entered English through scientific classification as biologists formalized the grouping of insects, crustaceans, and related animals. The same root 'arthron' gives us medical terms such as arthritis and arthralgia, which refer to joints, making these true cognates of arthropod.
How arthropod is actually used
Arthropod is a technical or scientific term used chiefly in biology, zoology, and education; it is more formal than everyday words like 'bug' or 'critter' and is standard in both British and American English with no significant regional variation.
Easily confused with arthropod
Despite sharing the 'arthro-' spelling pattern with words like arthritis, arthropod is an animal name and has no connection to verbs like annihilate.
Arthropathy is a medical term for disease of a joint, whereas arthropod refers to a joint-limbed invertebrate animal.