Answer:
Step-by-step explanation:
Invertebrates, as contrasted to vertebrates, are animals without a spinal column.
Most animals we interact with are vertebrates, such as cats, dogs, humans, etc.
There are 3 major types of animals (based of spinal cords, at least)
Vertebrates: Have a spine
Invertebrates: Spineless
Insects: Special case.
Anyways, away from that non sequitur,
Simply put: invertebrates are animals without spinal columns.