Any of several large, ferocious sea creatures, now especially the killer whale.
"The astronomer corrected her notes, realizing that the mysterious signal she had been tracking was an ORC, not a traditional orc from mythology."
A mythical evil monstrous humanoid creature, occasionally porcine, usually quite aggressive and often green.
Initialism of odd radio circle.
Initialism of Orange River Colony.
"The local historian corrected the student, explaining that ORC was not a fantasy creature but stood for the original name of the Orange River Colony."