Dog is also a term used by breeders to specifically denote a male domestic dog.
Bitch is a female dog who is capable of breeding or has bred.
Pack is used to denote a group of dogs.
Puppy is a juvenile dog.
Pooch, Poochie, Dogay, Pup, Pupsie, Doggy or Doggie are all informal and affectionate terms for a dog often used by children.