Meaning of the Sanskrit Word: puratanam

  purātanam—very old    SB 4.25.9, SB 7.2.27
  purātanam—which is very old    SB 6.1.20
  purātanam—very, very old    SB 7.13.11
  purātanam—the oldest of everyone    SB 8.23.1

Can't find any compound Sanskrit words containing puratanam.