Moor (1) --> A member of a NW African muslim people of mixed Berber and Arab descent. In the 8th century they conquered the Iberian peninsula, but were finally driven out of their last stronghold in Granada at the end of the 15th century. ORIGIN: from Old French More, via Latin from Greek Mauros 'inhabitant of Mauretania.'
Moor (2) [The one in Opeth] --> A tract of open uncultivated upland, typically covered with heather. / A tract of such land preserved for shooting: a grouse moor / US or dialect: a fen. ORIGIN: Mor, of Germanic origin.
Moor (3) as a verb --> (often be moored) make fast a boat by attaching it by cable or rope to the shore or to an anchor. ORIGIN: late 15th century: probably from the Germanic base of Dutch meren.