“Pluralize” and “Singularize” give meaningful naming conventions to the objects. In simple word it says do you want to represent your objects with the below naming convention:-

• One Customer record means “Customer” (singular).
• Lot of customer records means “Customer’s” ( plural , watch the “S”)

If you select the below check box entity framework generates naming convention which adheres to plural and singular coding convention.

Pluralize and Singularize