Confederation, n.
Etymology: [L. confoederatio: cf. F. confédération.]
1. The act of confederating; a league; a compact for mutual support; alliance, particulary of princes, nations, or states. The three princes enter into some strict league and confederation among themselves. Bacon. This was no less than a political confederation of the colonies of New England. Palfrey.
2. The parties that are confederated, considered as a unit; a confederacy. Articles of confederation. See under Article.
Shades of meaning
Fernald has no entry of its own for confederation; he lists it under alliance, association.
Where he writes about it:
In a confederacy or confederation there is an attempt to unite separate states in a general government without surrender of sovereignty. — from alliance
We speak of an alliance of nations, a club of pleasure-seekers, a community of Shakers, a company of soldiers or of friends, a confederacy, confederation, federation, or union of separate states under one general government, a partnership or company of business men, a conjunction of planets. — from association