Grader (noun)

1. A machine or person that is used to level and smooth the surface of a road, railway, or other area of land.
2. A person who evaluates or assigns a grade to something, such as a student's work or a product.

Origin:

Early 19th century (as a verb in the sense "level (land)"): from grade + -er. a grader is a machine or person that is used to level and smooth the surface of a road, railway, or other area of land.

Examples:

1. The grader leveled the surface of the road.
2. The grader operator smoothed out the gravel.
3. The teacher is the grader of the student's homework.
4. The grader of the exam gave high marks to the student.
5. The grader of the product gave it a high rating.