Abarim Publications' online Biblical Hebrew Dictionary
There are four different roots that are all spelled כפר (kpr) There doesn't seem to be an etymological relationship between these four, but their similarities may have prompted the poetic writers of the Bible to engage in word play.
The important root כפר (kpr I) may originally have had to do with covering or hiding, but in the Bible it appears to be used solely in the sense of to atone or purge, with the objective of rightful freedom. It yields the following derivations:
- The masculine noun כפר (koper), meaning the price of a life; a price of ransom of a life (Exodus 21:30, Job 33:24, Isaiah 43:3).
- The verb כפר (kapar), meaning to atone or purge. This verb is formed from the noun, but occurs much more often than the noun (Genesis 32:21, Leviticus 16:32, 2 Samuel 21:3).
- The plural noun כפרים (kippurim), meaning atonement(s) as used in the expression יום כפרים (yom kippurim); the day of atonements. The plural form was probably used as an intensifier. Today this day is known in the singular form: Yom Kippur.
- The noun כפרת (kapporet), the technical term for the cover of the Ark of the Covenant, known as the Mercy Seat. Mercy Seat is an improper translation. Better would have been Place Of Atonement (as proposed by HAW Theological Wordbook of the Old Testament).
The verb כפר (kapar) is in every way identical to the previous verb, but instead of meaning to atone, it means to cover over, specifically with pitch. It's used only once, in Genesis 6:14, where Noah is to cover the hull of the Ark with pitch. This verb comes from the masculine noun כפר (koper), which happens to be identical to the previous noun. But this time it means pitch. And it's only used in Genesis 6:14.
These words are probably imported from other languages but the similarities with the previous root are too obvious to ignore. BDB Theological Dictionary makes no mention of any relation between the two and HAW Theological Wordbook of the Old Testament limply states that the two "should probably be distinguished". Here at Abarim Publications we see no compelling reason to do so.
The third root כפר (kpr) seems to be a catch-all for words that have no clear etymology:
- The masculine noun כפיר (kepir), which is one of a few words meaning lion. This word seems to particularly denote a young lion.
- The masculine noun כפר (koper), which is identical to the two previous nouns כפר (koper). This time it denotes some kind of plant, perhaps henna. BDB Theological Dictionary says: "a shrub or low tree, with fragrant whitish flowers goring in clusters like grapes".
- The masculine noun כפר (kapar), meaning village.
- The masculine noun כפר (koper), which is identical to the previous three versions of כפר (koper). This time it means village, and is probably a variant of the previous noun.
The assumed fourth root כפר (kpr) yields two identical masculine nouns כפור (kepor), one of which denotes a bowl of gold or silver as used in the temple, and we can't help but wonder whether this bowl was perhaps a bowl overlain with gold or silver leaf (1 Chronicles 28:17, Ezra 1:10). The other noun כפור (kepor) means hoar frost, which obviously covers everything with a thin layer of ice (Exodus 16:14, Psalm 147:16).