tadpole
tad.pole \'tad-.po-l\ n [ME taddepol, fr. tode toad + polle head - more at POLL)M : a larval amphibian; specif : a frog or toad larva that has a rou nded body with a long fin-bordered tail and external gills soon replaced by internal gills and undergoes a metamorphosis in which adult structures are attained