borg n.

"a man-machine hybrid, a human modified by integrated machinery to have extended powers," 1960, a blend of the first elements of cybernetic and organism.

in the internet sense, c. 2000, short for robot. Modern use has coincidental affinities with earlier uses, such as "parasitical worm or maggot" (1520s), which is of unknown origin; and Australian-New Zealand slang "worthless, troublesome person" (World War I-era). The method of minting new slang by clipping the heads off words does not seem to be old or widespread in English. Examples (za from pizza, zels from pretzels, rents from parents) are American English student or teen slang and seem to date back no further than late 1960s. Also compare borg, droid.