reconciliation based on covering offenses

2643 katallage
from 2644; TDNT-1:258,40; {See TDNT 50} n f
AV-reconciliation 2, atonement 1, reconciling 1; 4
1) exchange
1a) of the business of money changers, exchanging equivalent values
2) adjustment of a difference, reconciliation, restoration to favour
2a) in the NT of the restoration of the favour of God to sinners that repent and put their trust in the expiatory death of Christ

03725 kippur
from 03722; n m pl; {See TWOT on 1023 @@ "1023b"}
AV-atonement 8; 8
1) atonement

03722 kaphar
a primitive root; v; {See TWOT on 1023} {See TWOT on 1024} {See TWOT on 1025} {See TWOT on 1026}
AV-atonement 71, purge 7, reconciliation 4, reconcile 3, forgive 3, purge away 2, pacify 2, atonement … made 2, merciful 2, cleansed 1, disannulled 1, appease 1, put off 1, pardon 1, pitch 1; 102
1) to cover, purge, make an atonement, make reconciliation, cover over with pitch
1a) (Qal) to coat or cover with pitch
1b) (Piel)
1b1) to cover over, pacify, propitiate
1b2) to cover over, atone for sin, make atonement for
1b3) to cover over, atone for sin and persons by legal rites
1c) (Pual)
1c1) to be covered over
1c2) to make atonement for
1d) (Hithpael) to be covered

Atonement ~ kaphar
By Jeff A. BennerThe Hebrew word kaphar means "to cover over" such as a lid and is the word for the lid of the ark of the covenant (though many translations translate this as mercy seat for no etymological reason). This word is translated as pitch which was spread over the ark in order to make it water tight (Genesis 6:14) This same word is also translated as a atonement. The word atonement is an abstract but in order to understand the true Hebrew meaning of a word we must look to the concrete meaning. If an offense has been made the one that has been offended can act as though the offense is covered over and unseen. We express this idea through the word of forgiveness. Atonement is an outward action that covers over the error.  http://www.ancient-hebrew.org/27_atonement.html