Meaning of the Sanskrit Word: vajrena

  vajreëa—with the thunderbolt    SB 6.12.3, SB 6.12.25, SB 8.11.18
  vajreëa—by the thunderbolt    SB 6.12.32, SB 8.11.6
  vajreëa—by his thunderbolt    SB 6.18.62

Can't find any compound Sanskrit words containing vajrena.