* 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.

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. (Zoöl.) See Frog hopper. -- Frog hopper (Zoöl.), a small, leaping, hemipterous insect living on plants. The larvæ are inclosed in a frothy liquid called cuckoo spit or frog spit. -- Frog lily (Bot.), the yellow water lily (Nuphar). -- Frog spit (Zoöl.), the frothy exudation of the frog hopper; -- called also frog spittle. See Cuckoo spit, under Cuckoo.