Is it farther or further?
mid-14c., "deathlessness," from Old French immortalité (13c.) and directly from Latin immortalitatem (nominative immortalitas) "deathlessness, endless life," from immortalis (see immortal). Sense of "everlasting fame" is from 1530s.
perpetuity of existence. The doctrine of immortality is taught in the Old Testament. It is plainly implied in the writings of Moses (Gen. 5:22, 24; 25:8; 37:35; 47:9; 49:29, comp. Heb. 11:13-16; Ex. 3:6, comp. Matt. 22:23). It is more clearly and fully taught in the later books (Isa. 14:9; Ps. 17:15; 49:15; 73:24). It was thus a doctrine obviously well known to the Jews. With the full revelation of the gospel this doctrine was "brought to light" (2 Tim. 1:10; 1 Cor. 15; 2 Cor. 5:1-6; 1 Thess. 4:13-18).
in philosophy and religion, the continuity of human spiritual existence after the death of the body. The concept of immortality is to be distinguished from that of bodily resurrection.