/ ɒnˈtɒlədʒi; NAmE ɑːnˈtɑːl-/ noun
[ U ] a branch of philosophy that deals with the nature of existence
► onto·logic·al / ˌɒntəˈlɒdʒɪkl; NAmE ˌɑːntəˈlɑːdʒ-/ adjective
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WORD ORIGIN
early 18th cent.: from modern Latin ontologia , from Greek ōn , ont- being + -logy .