An invertebrate is an animal that lacks a backbone (spinal column). This group includes a vast array of creatures, such as:
* Insects: Ants, beetles, butterflies, etc.
* Mollusks: Snails, clams, squid, etc.
* Worms: Earthworms, roundworms, etc.
* Spiders: Spiders, scorpions, ticks, etc.
* Jellyfish: Jellyfish, corals, anemones, etc.
If you were looking for the meaning of "invertebrate", hopefully this explanation helps!