Galvanized Pipe: This refers to the process of applying a protective zinc coating to steel pipes to prevent corrosion. Galvanized pipes are known for their durability and resistance to rust, making them suitable for various applications, particularly where moisture is present. 

Nominal Pipe Size (NPS): This indicates the nominal size of the pipe, which is essentially a label used to identify the approximate internal diameter. In this case, it's 2 inches. However, it's important to note that the actual outer diameter of the pipe may vary due to manufacturing tolerances. 

 For instance, the outer diameter of a 2-inch NPS pipe is typically around 2.375 inches. 

Schedule 40: This denotes the thickness of the pipe wall and its pressure rating. Schedule 40 pipes have a thicker wall compared to pipes with lower schedule numbers (e.g., Schedule 10 or Schedule 20), providing greater strength and durability. The "40" in Schedule 40 indicates the pressure rating, which is approximately 2,000 psi. 

 The actual wall thickness of a 2-inch NPS Schedule 40 pipe is around 0.154 inches.