A puppy is a young dog, usually under a year old, though people sometimes call dogs puppies until they're about 18 months old. Puppies are born tiny, with their eyes closed, and they spend their first weeks mostly sleeping and drinking their mother's milk. By the time they're eight weeks old, they're often ready to go to new homes.

Puppies are famous for being playful, curious, and clumsy. A puppy will chase anything that moves, chew on almost everything it can reach, and sometimes trip over its own oversized paws. They need lots of patience and training because they don't naturally know the rules of living in a house. A puppy might have an accident on the carpet, chew up a favorite shoe, or bark at its own reflection because it hasn't learned better yet.

The word can also describe the young of some other animals in the dog family, like foxes, though people usually say fox pup instead of puppy. Sometimes people playfully call anyone young and inexperienced a puppy, like a puppy doctor fresh out of medical school, though this usage is less common.

Raising a puppy takes serious work: feeding it the right food, taking it outside frequently, teaching it basic commands, and giving it plenty of exercise and attention. For people who love dogs, watching a puppy grow into a loyal, well-trained companion can make all that effort feel worthwhile.