ungual ungual an ungual (from latin unguis, i.e. nail) is a highly modified distal toe bone which ends in a hoof, claw, or nail. elephants and ungulates have ungual phalanges, as did the sauropods and horned dinosaurs. a claw is a highly modified ungual phalanx. an ungual of the ground sloth eremotherium as an adjective, ungual means related to nail, as in periungual (around the nail).