- The definition of an invertebrate is an animal without a backbone.
Any animal other than a fish, reptile, amphibian, bird or mammal is an example of an invertebrate.
A spider is an example of an invertebrate.
- not vertebrate; having no backbone, or spinal column
- of invertebrates
- having no moral backbone; lacking courage, resolution, etc.
Origin of invertebrateModern Latin invertebratus
- Lacking a backbone or spinal column; not vertebrate.
- Of or relating to invertebrates: invertebrate zoology.
(comparative more invertebrate, superlative most invertebrate)
- Lacking a backbone.