From the Gaelic - it would mean the black (dhu) rock (craig).
It's a phonetic English spelling of the Gaelic dubh(black).
Dhu is an expession example " todays monday right?" "no dhu"
From the Gaelic marag-dhubh, pronounced 'mara-ghoo'"Marag dhu" refers to a traditional Scottish sausage or "pudding" which is in English is often called "Blood Pudding"The basic ingredients are Oatmeal, suet, salt, pepper and for n=marag dhu cows or pigsblood.Marag-gheal is 'white pudding/oatmeal'.
LOCH LINNHE IS ABOUT 450 FEET DEEP WHICH IS DEEPER THAN THE NORTH SEA.
"Please" loosely and "With your will" literally are English equivalents of the Irish Gaelic phrase le do thoil. One of the pronunciation possibilities is "leh dhu hull" in Gaelic.
That is the name of the artist. He was Scottish.
Roderick Dhu Sutherland was born in 1862.
Roderick Dhu Sutherland died in 1915.
Dallas Dhu distillery was created in 1899.
Dallas Dhu distillery ended in 1983.
Doinall Dhu O'Connor was born in 1894.