Invertebrate is a term used to describe any animal without a backbone or spinal column.
The giant squid, which until recently had not been observed alive in its adult form, is the largest invertebrate; although it is possible that the colossal squid is even larger.
The following are descriptions of some well-known invertebrate phyla.
The term invertebrate was coined by Jean-Baptiste Lamarck, who divided these animals into two groups, the Insecta and the Vermes.