severed vs stand-alone

severed

adj
  • Separated, cut off or broken apart. 

stand-alone

adj
  • Operating, functioning, or existing without additions or assistance; independent; able to be separate or separated. 

noun
  • A device that can operate on its own, rather than as an accessory for another device. 

  • Something that is not a part of some series or sequence. 

How often have the words severed and stand-alone occurred in a corpus of books? (source: Google Ngram Viewer )