It may well be, and especially if we submit to the tyranny of words of the expense of the political realities they express. We need first, therefore, to ask what it is to which the words confederation and federation actually refer. It is not the words that matter, but what they mean in practice. To take confederation first, a confederation comes about when two or more states agree in their own interets to develop common policies in a number of areas of government, as, say, in foreign affairs, defense, or public health. All the states involved have, in principle, to agree to joint policies and their administration.
Unanimity is the rule and secession is always possible.
However, it does happen in practice that a state will be allowed to opt out of a particular policy and still remain in the confederation, especially in relatively minor matters. However, in the last resort unanimity matters, as in the case of the accession of new states to the European Union, which is in many respects still a confederation. It is formed when two or more states agree to transfer their sovereignty in certain, and usually major, areas of policy to common or federal instituions. An inevitable consequence in democratic states is that the people of the federation as a whole now begin to relate to, and want to influence, federal decisions, usually by way of an elected legislative assembly. Moreover, federation-wide interest and pressure groups develop, as in the United states and Switzerland.