| Term | Definition |
| Achilles Tendon | A tendon at the back of the ankle that connects the calf muscles and the heel; named after the mythical Greek hero. |
| Auditory Nerve | Nerve endings that make up the ear's main connection to the brain. |
| bones | The hard part made up of minerals and tissue that protect body's internal organs and work to allow the body to move. |
| cartilage | A tough elastic tissue that helps keep bones from grinding against each other. |
| Joint | The point two bones meet. |
| Skeleton | The 206 bones of the body. |
| brain | The organ that controls thought, memory, and feelings |
| cerebellum | The part of the brain that lets you make coordinated movements, or careful movements you can control. |
| calcified | Hardened by deposits of calcium salt |
| characteristic | A typical or unique feature |
| classify | To group and study the relationships between organisms |
| cold-blooded | Adjective describing animals whose internal body temperature varies with the temperature of its surroundings |
| diaphragm | An important muscle located between the chest and the abdomen in mammals used in breathing. |
| feather | A structure that forms the external covering of birds and assists in flight, insulation or both. |
| Cerebrum | The biggest part of the brain that is responsible for voluntary muscle movement, dream, thoughts, memories, language and communications |
| Pelvis | Surrounds and protects the bladder, intestines and in women the reproductive organs |
| Reflex | Involuntary movement as a result of unexpected stimulus |