n. [ L. bufo toad: cf. F. bufonite. ] (Paleon.) An old name for a fossil consisting of the petrified teeth and palatal bones of fishes belonging to the family of Pycnodonts (thick teeth), whose remains occur in the oölite and chalk formations; toadstone; -- so named from a notion that it was originally formed in the head of a toad. [ 1913 Webster ]