or ‧ ni ‧ thol ‧ o ‧ gy /ˌɔːnəˈθɒlədʒi, ˌɔːnɪˈθɒlədʒi $ ˌɔːrnəˈθɑː-/ BrE AmE noun [uncountable]
[ Date: 1600-1700 ; Language: Modern Latin ; Origin: ornithologia , from Greek ornis 'bird' ]
the scientific study of birds
—ornithological /ˌɔːnəθəˈlɒdʒɪk ə l◂, ˌɔːnɪθəˈlɒdʒɪk ə l◂ $ ˌɔːrnəθəˈlɑː-/ adjective