The word "Molossus" refers to a large and powerful breed of dog, but it can also be used as a synonym for the term "Mastiff". Other synonyms for Molossus or Mastiff include "Bullmastiff", "Great Dane", and "Saint Bernard". These dogs are known for their impressive size, strength, and loyalty to their owners. They have been used for hunting, guarding, and as working dogs throughout history. No matter what synonym is used, it is important to remember that these dogs require proper training, socialization, and care to ensure they remain healthy and happy.