Final answer:
The correct documentation for an area of skin rubbed away by friction is an 'abrasion.' It is a superficial wound that can be painful and should be kept clean to prevent infection.
Step-by-step explanation:
The area near the elbow that has been rubbed away by friction, as observed by the nurse following the child's bicycle fall, should be documented as an abrasion. Abrasions occur when the skin is scraped off due to an object rubbing against it, typically resulting in a superficial wound that can be painful, but generally not deep or life-threatening. The nurse should clean and protect the affected area to prevent any potential infection as pathogens could enter through the break in the skin.