| A colorless, odorless, non-combustible gas, heavier than air; can be compressed into a super cold solid known as dry ice; changes from solid to vapor at- 78.5C. | |
| The conditions that exist in a working electrical current. A current that is unbroken, not open. | |
| A rotating shaft that rotates another part, such as it wheel. | |
| A device attached to a mechanically driven cooling fan that allows the fan to freewheel when the engine is cold and the vehicle is driven at speed. |