What defines a shepherd and mastiff type dog?

There are many shepherd type dogs and many mastiff type dogs. There are also many dogs that look a lot like a shepherd yet aren't a shepherd and there are many really big dogs that aren't mastiffs. Have I confused you enough yet? My question is...what makes a shepherd dog a shepherd dog and what makes a mastiff a mastiff?I want to know what defines shepherd type dogs and mastiff type dogs, not the german shepherd and mastiff breeds. Sorry for any confusion.

you're best bet is to do a search on dog breeds and read the information about each breed and it's temperament, color, size, origin, etc..I could take you by the hand and guide you through this process but it's better you do it on your own and if you need assistance ask me.

A lot of times with a shepherd breed, they'll have a curvation of the lower back(or so it appears) with a straight, stout chest and a somewhat bushy tail. This goes unless of course, something has happened to it or it's a mixed breed. With a mastiff, it's more of a husky(not the dog) breed. More muscle definition is shown. They won't have as much fur. A lot of times, they'll have a skinnier tail or so it appears due to lack of fur. Fatter jowls are a common attribute. Straighter legs, which is basically not so much a lean as you would get with say a German Shepherd. But yeah, that's my take on it.Hope it helps. : )

Mastiff-types are massive - muscular, broad chested, and tall. They have rounded, dome-shaped skulls. They have a pronounced stop (the spot where the muzzle protrudes from the head - Collies do not have a pronounced stop, if that helps). Their eyes often appear to be deep-set. Most have very short fur, but not all. Most have droopy ears that are set wide on the head.Shepherd-types are medium to large. They are more narrow and lithe. They have long narrow muzzles. Their ears are erect and set on top of the head. They usually have denser coats. They have a somewhat deep chest (there should be a definite rise in the body line from the chest to the stomach). Their backs may slope down toward the hindquarters.