Entry 1 sense Webster, 1913 Protozoan /prōtˌ-əz-ō'-ən/ · Pro·to·zo·an · IPA /ˌpɹoʊ.təˈzoʊ.ən/ 01 a. Of or pertaining to the Protozoa. 1. Of or pertaining to the Protozoa.(Zool.) See: Protozoa