A "big dog" typically refers to a large breed of dog, often weighing over 50 pounds. Common examples include breeds like Labrador Retrievers, German Shepherds, and Saint Bernards. These dogs are known for their strength and size, which can make them suitable for various roles, including service animals, working dogs, and family pets. Big dogs often require more space, exercise, and food compared to smaller breeds. They can be friendly and loyal companions, but proper training and socialization are essential to ensure they behave well around people and other animals. Their size can also make them more challenging to manage, especially for inexperienced dog owners.