Concise Bible Dictionary:
In the Old Testament, except in Exodus 21:30, the word is kopher, literally “a covering,” a cognate word to kaphar, often translated “atonement.” None “can by any means redeem his brother, nor give to God a ransom for him” (Psa. 49:7). But God could say, “Deliver him from going down to the pit: I have found a ransom” (Job 33:24). The word occurs also in Exodus 30:12; Job 36:18; Proverbs 6:35; Proverbs 13:8; Proverbs 21:18 and Isaiah 43:3. In the New Testament it is λύντρον, or ἀντίλυιρου, from “to loose, set free.” Christ gave Himself, His life, a ransom for many: the precious blood of Christ witnesses that every claim of God against the believer has been answered (Matt. 20:28; Mark 10:45; 1 Tim. 2:6).
Strong’s Dictionary of Greek Words:
Meaning:
from 3089; something to loosen with, i.e. a redemption price (figuratively, atonement)