ラテン語のOrcus(地獄の悪魔)が語源で、語源的にはogre(鬼)、orca(シャチ)と同じ。 後に『ロード?オブ?ザ?リング』の作者J.R.R.トルキンが中つ国のオークを指す言葉として借用した。
But Orcs and Trolls spoke as they would, without love of words or things; and their language was actually more degraded and filthy than I have shown it. ["Return of the King," 1955]