Confederacy
Part of speech: noun
Definition: an alliance
Example sentence: The United States form a young republic, a confederacy which ought ever to be cemented by a union of interests and affection, under the influence of those principles which obtained their independence.
Confederation
Part of speech: noun
Definition: A union or alliance of states or political organizations.The act of forming an alliance.
Example sentence: Our articles of confederation ought to be revised and measures immediately taken to invigorate the Continental Union. Depend upon it: there lies the danger for America. This last stroke is wanting, and unless the states be strongly bound to each other, we have to fear from British and, indeed, from European politics.