The Old English word appearing in Beowulf as a source for Tolkien’s orc concept is orcneas.
The word occurs in the Old English poem Beowulf in a passage describing the monstrous descendants of Cain. Tolkien was a major Beowulf scholar and knew the poem’s language and manuscript tradition closely. The term helped provide an ancient linguistic association for the creatures he called Orcs.
Tolkien used several related forms during the development of his legendarium, including orc and orch. In his fictional languages, the word became associated with hostile, corrupted beings serving powers such as Morgoth and Sauron. The literary concept therefore combines Old English inspiration with Tolkien’s own invented history and languages.
Orcneas should not be confused with warg, which refers to a wolf-like creature, or with eoten, an Old English word associated with giants. The Beowulf passage is a source of linguistic inspiration, not a complete description of Tolkien’s Orcs.