Entry 2 senses · 2 variants Webster, 1913 Amphibian /(-an)/ · Am·phib·i·an · IPA /æmˈfɪbɪən/ a. n. 01 a. Of or pertaining to the Amphibia; as, amphibian reptiles. 1. Of or pertaining to the Amphibia; as, amphibian reptiles.(Zool.) 02 n. One of the Amphibia. 1. One of the Amphibia.(Zool.)