Obedience class command is a term used to refer to the commands that are taught in obedience classes. The two most common commands are 'SIT' and 'HEEL', which are three and four letter words respectively. SIT is a command that tells the dog to SIT down, while HEEL is a command that tells the dog to stay close to its owner's side. Both commands are important for teaching a dog basic obedience and good behavior.