noun (n)

• a soft heavy toxic malleable metallic element; bluish white when freshly cut but tarnishes readily to dull grey(noun.substance)

  Synonym:
  atomic number 82, lead
  

  source: wordnet30
• a unit of information equal to 1000 terabits or 10^15 bits(noun.quantity)

  Synonym:
  pbit, petabit
  

  source: wordnet30
• a unit of information equal to 1000 terabytes or 10^15 bytes(noun.quantity)

  Synonym:
  petabyte
  

  source: wordnet30
• a unit of information equal to 1024 tebibytes or 2^50 bytes(noun.quantity)

  Synonym:
  pebibyte, petabyte, pib
  

  source: wordnet30