Greek: αθανασια [athanasia] (Noun feminine). From α [a] (as a negative particle) and θανατος [thanatos] "death": Immortality.
αθανασια [athanasia] appears 3 times in the NT:
(1) 1 Corinthians 15: 53
For this corruptible must put on incorruption, and this mortal must put on immortality. - αθανασιαν [athanasian] Accus. sing.
(2) 1 Corinthians 15: 54
So when this corruptible shall have put on incorruption, and this mortal shall have put on immortality, then shall be brought to pass the saying that is written, Death is swallowed up in victory. - αθανασιαν [athanasian] Accus. sing.
(3) 1 Timothy 6: 16
Who only hath immortality, dwelling in the light which no man can approach unto; whom no man hath seen, nor can see: to whom be honour and power everlasting. Amen. - αθανασιαν [athanasian] Accus. sing.