Meaning of the Sanskrit Word: amrtatvaya

  amrtatvaya—for eternal life    SB 3.24.38
  amrtatvaya—for becoming eternal    Madhya 8.89
  amrtatvaya—the eternal life    Adi 4.23
  amrtatvaya—for becoming eternal associates of the Lord    Madhya 13.160
  amrtatvaya—for liberation    Bg 2.15

Can't find any compound Sanskrit words containing amrtatvaya.