/duy me"treuh don'/ , n.
an extinct carnivorous mammallike reptile, of the genus Dimetrodon, dominant in North America during the Permian Period, up to 10 ft. (3.1 m) long and usually bearing spinal sails.
[ dímetr ( os ) having two measures (see DIMETER) + odón tooth; appar. so named in reference to the large size of the anterior incisors relative to the other teeth ]