syncretize
Concise Oxford English Dictionary © 2008 Oxford University Press:
syncretize /ˈsɪŋkrɪtʌɪz/ (or syncretise)
▶verb attempt to amalgamate (differing religious beliefs, schools of thought, etc.).
– derivatives
syncretization noun.
syncretization noun.
'syncretize' also found in these Oxford entries:

