Sheepdog and Working dog

Sheepdog noun - Any of various usually long-haired breeds of dog reared to herd and guard sheep.

Working dog and sheepdog are semantically related. In some cases you can use "Working dog" instead a noun "Sheepdog".

Working dog noun - Any of several breeds of usually large powerful dogs bred to work as draft animals and guard and guide dogs.

Sheepdog and working dog are semantically related. Sometimes you can replace term "Sheepdog" with "Working dog", this terms are similar.