I don't know anything about George Macdonald, but you're correct that Tolkien is attributed with the creation of the common modern concept of orcs.
The word has roots in old english and has been present in fairy tales since as long ago as Beowulf, but Tolkien gave the term its current connotations and association with that specific sort of creature.
Thanks for bringing up Beowulf. Classic. In oh so many ways : )
Just in case some of you haven't heard, there really is nothing new under the sun (or, because there is the occasional original thought, not very much new under the sun : ). Not a put down. But really, not sure what the discussion is about? Oh yeah, everyone is worried about "copying" and/or "plagiarism' nowadays. What a joke. We're all lawyers now?
That said, I thoroughly enjoyed (and go through the book series every few years) Tolkien. He put his own spin on timeless ideas. Great author. Neat story/plot/characters. I also enjoyed the movies. Looking forward to the Hobbit movie duo.
(edit spelling, punctuation, etc.)
Tarl