• (n.) A Mexican spinous lizard (Phrynosoma orbiculare) having a head somewhat like that of a toad; -- called also horned toad.
<zoology> A Mexican spinous lizard (Phrynosoma orbiculare) having a head somewhat like that of a toad. ... Synonym: horned toad. ... (01 Mar 1998) ... 
Ta`pa·yax'in noun (Zoology) A Mexican spinous lizard ( Phrynosoma orbiculare ) having a head somewhat like that of a toad; -- called also horned toad .