Entry 1 sense Webster, 1913 Ornithologist · Or·ni·thol·o·gist · IPA /ˌɔɹnɪˈθɑləd͡ʒɪst/ 01 n. One skilled in ornithology; a student of ornithology; one who describes birds. 1. One skilled in ornithology; a student of ornithology; one who describes birds.