K9, or canine, refers to domesticated dogs that are often trained for specific tasks. These tasks can include search and rescue, detection of drugs or explosives, and assisting law enforcement. K9 units are commonly used by police departments and military organizations to enhance safety and efficiency in various operations. The term "K9" is derived from the word "canine," which is the scientific classification for dogs and their relatives. K9s are known for their strong sense of smell, intelligence, and loyalty, making them valuable partners in many fields, including search and rescue, law enforcement, and military operations.