Meaning

noun a flat-bottomed motor vehicle that can travel on land or water

noun an airplane designed to take off and land on water

noun cold-blooded vertebrate typically living on land but breeding in water; aquatic larvae undergo metamorphosis into adult form

originLearned borrowing from Latin amphibius [from Ancient Greek ἀμφίβιος (amphíbios), from ἀμφίς (amphís, “of both kinds”) + βίος (bíos, “life”)] + -an.

Etymology from Wiktionary, CC BY-SA 3.0