Final answer:
The white, square sign with black lettering is a stop sign that instructs drivers to come to a complete stop at the intersection before proceeding.
Step-by-step explanation:
The white, square sign with black lettering that you are referring to is a stop sign. It instructs drivers to come to a complete stop at the intersection before proceeding. This sign is used to regulate traffic and ensure the safety of all road users. It is important to obey stop signs to prevent accidents and maintain order on the roads.