Entry 1 sense Webster, 1913 Pterodactyl · Pter·o·dac·tyl · IPA /ˌtɛɹəˈdæktl̩/ 01 n. An extinct flying reptile; one of the Pterosauria. See Illustration in Appendix. 1. An extinct flying reptile; one of the Pterosauria. See Illustration in Appendix.(Paleon.)