1) to change, exchange, as coins for others of equivalent value
1a) to reconcile (those who are at variance)
1b) return to favour with, be reconciled to one
1c) to receive one into favour
Part of Speech: verb
Citing in TDNT: 1:254, 40
From G2596 and G236; to change mutually, that is, (figuratively) to compound a difference: - reconcile.
These two sites give similar information, with the definition from several dictionaries and statistics on the use of the word.
Perseus Digital Library
University of Chicago's Logion lexicon
Thayer's dictionary plus other information.
From this site's dictionary (in Italian)
Click on the first column to search for that word as a form of the root καταλλάσσω; click on the second column to search for that grammatical form of the root καταλλάσσω; click on the third column to search for that word and grammatical form; click on the total to search for the root καταλλάσσω.