syncretism

Concise Oxford English Dictionary © 2008 Oxford University Press:
syncretism /ˈsɪŋkrɪtɪz(ə)m/

▶noun

• 1 the amalgamation of different religions, cultures, or schools of thought.

• 2 Linguistics the merging of different inflectional varieties of a word during the development of a language.

– derivatives
syncretic adjective,
syncretist noun & adjective,
syncretistic adjective.

– origin C17: from mod. L. syncretismus, from Gk sunkrētismos, from sunkrētizein ‘unite against a third party’, from sun- ‘together’ + krēs ‘Cretan’ (orig. with ref. to ancient Cretan communities).