Original: The title of Formula One World Champion Constructor is awarded to the car "make" that has scored the most points during the course of the season, where a car's make takes into account both engine and chassis. Hence, if a car's chassis and engine constructor are the same entity (e.g. Ferrari, Toyota, BRM etc.) then the make is simply the name of that one constructor.
Simplified: If a car's chassis and engine are made by the same entity, then the constructor is the car make.