noun

• (archaic) Any of several large, ferocious sea creatures, now especially the killer whale.

noun

• (fantasy, mythology) A mythical evil monstrous humanoid creature, usually quite aggressive and often green.
  "Who at one stroke didst pare away three heads from off the shoulders of an Orke, begotten by an Incubus."
• (slang, derogatory) A Russian soldier or gangster.
  "Ukrainians themselves, including those on the right, preferred to call the events the 'Revolution of Dignity', depicted not in terms of ethnicity or class, but in simple civic black and white – a revolution of the people against Yanukovych's 'Mordor' and his 'Orcs'."
• (by extension, Internet slang, ethnic slur) A Russian person.

noun

• (astronomy) Acronym of odd radio circle, a very large unexplained astronomical object.
  "Even those who never look into the night sky and wonder about stars or galaxies may find the new research interesting, Diamond-Stanic said, because ORCs help to explain how the galaxy we live in came to be."
• (biochemistry) Initialism of origin recognition complex.

noun

• (slang, fiction, derogatory) Alternative form of orc (monstrous warrior in fantasy; Russian soldier)