Douglas Harper's Etymology Dictionary
Wiktionary
a. Operating, functioning, or existing without additions or assistance; independent; able to be separate or separated.
WordNet
adj. capable of operating independently
Usage examples of "stand-alone".
Maybe those ciliated protozoa that had a variant genetic code were descended from some cilia who had been in symbiosis with other cells in the past, developing genetic-code variations for the same safety-net reasons mitochondria had but, unlike the cilia we still retained, had subsequently broken off the symbiosis and returned to stand-alone life.
West's expert eye skimmed over stand-alone tools such as a drill press, a drum sander, bench grinder, jointer, thickness planer, shaper, and all the expected chisels, Forstner bits, wire-brush wheels, brad-point bits, plug cutter, countersink set.
Scindex is a whole, self-contained, stand-alone, instant self-publishing and self-assembly system.
It wasn't like it couldn't be donehe'd nagged O'Brien into fitting the ICU with an uninterruptable power supply the first month he was on the stationand God knew he had little other use for the three stand-alones currently taking up space in the back room storage locker.