Frog n. 1.(Zool.) An amphibious animal of the genus Rana and related genera, of many species. Frogs swim rapidly, and take long leaps on land. Many of the species utter loud notes in the springtime. Note: The edible frog of Europe (Rana esculenta) is extensively used as food; the American bullfrog (R. Catesbiana) is remarkable for its great size and loud voice.
2.(Anat.) The triangular prominence of the hoof, in the middle of the sole of the foot of the horse, and other animals; the fourchette.
3.(Railroads) A supporting plate having raised ribs that form continuations of the rails, to guide the wheels where one track branches from another or crosses it.
4.An oblong cloak button, covered with netted thread, and fastening into a loop instead of a button hole.
5.The loop of the scabbard of a bayonet or sword.
Cross frog (Railroads), a frog adapted for tracks that cross at right angles.
Frog cheese, a popular name for a large puffball.
Frog eater, one who eats frogs; a term of contempt applied to a Frenchman by the vulgar class of English.
Frog fly. (Zool.) See Frog hopper. Frog hopper (Zool.), a small, leaping, hemipterous insect living on plants. The larvae are inclosed in a frothy liquid called cuckoo spit or frog spit.
Frog lily (Bot.), the yellow water lily (Nuphar).
Frog spit (Zool.), the frothy exudation of the frog hopper; called also frog spittle. See Cuckoo spit, under Cuckoo. 
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