peripheral

Adjective

• related to the key issue but not of central importance
  • a peripheral interest
    
  • energy is far from a peripheral issue in the economy
    
  • peripheral issues
    

• on or near an edge or constituting an outer boundary; the outer area
  • Russia's peripheral provinces
    
  • peripheral suburbs
    

Noun

• (computer science) electronic equipment connected by cable to the CPU of a computer
  • disk drives and printers are important peripherals
    

Related words

• Synonyms: 
  computer peripheral , peripheral device