Frogs, salamanders, newts, and caecilians belong to the vertebrate class Amphibia.
Amphibia is the class traditionally called the amphibians. Living members are grouped within the subclass Lissamphibia and fall into three living orders: Anura, which includes frogs and toads; Caudata or Urodela, which includes salamanders and newts; and Gymnophiona, which includes the limbless caecilians.
The name amphibian comes from Ancient Greek words meaning “both kinds of life,” reflecting the group’s traditional association with aquatic and terrestrial environments. Many amphibians begin life as aquatic larvae, such as tadpoles, and later undergo metamorphosis into air-breathing adults. Their permeable skin can also participate in respiration.
The answer is not Reptilia, even though some amphibians resemble small reptiles. Amphibians are ectothermic, anamniote tetrapods, while reptiles, birds, and mammals are amniotes. “Amphibia” names the class; “Lissamphibia” is the more specific living clade containing all modern amphibians.