invertebrate
n. countablen. an animal that does not have a backbone. This includes creatures like insects, spiders, worms, and jellyfish.
n. an animal lacking a vertebral column or backbone. This category encompasses the vast majority of animal species, including arthropods, molluscs, and cnidarians.
The garden is full of insects, which are invertebrates.
Marine biologists spent the afternoon cataloging various invertebrates found in the tide pools along the rocky shore.
While vertebrates are often the focus of public interest, invertebrates play a critical role in ecosystem health, serving as primary pollinators and decomposers in nearly every habitat on Earth.
From in- + vertebrate.
Etymology adapted from Wiktionary, available under CC BY-SA 4.0.
Last updated May 28, 2026