Evolutionary grade
However, we now know that amphibia gave rise to early egg-laying amniotes. These gave rise to sauropsids (the ancestors of reptiles and birds) and synapsids (the ancestors of mammals. 'Reptile' is just a common term for those sauropsids which survived to the present day, minus the birds. As an everyday word, everyone understands it. But as a modern scientific term, it is no longer good, and is less used.