Old English sheepdog and Sheep dog

Old English sheepdog noun - Large sheepdog with a profuse shaggy bluish-grey-and-white coat and short tail; believed to trace back to the Roman occupation of Britain.

Sheep dog and Old English sheepdog are semantically related. In some cases you can use "Sheep dog" instead a noun phrase "Old English sheepdog".

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

Old English sheepdog and sheep dog are semantically related. Sometimes you can replace phrase "Old English sheepdog" with "Sheep dog", this phrases are similar.