(fed′ər·əl) adjective
1. Govt. Of or pertaining to a form of government in which certain states agree by compact to grant control of common affairs to a central authority but retain individual control over internal affairs.
2. Of or pertaining to a union or central authority so established.
3. Favoring or supporting a government formed by a union of several states.
4. Relating to, arising from, or founded upon a league or covenant.
—noun An advocate of federalism. [<F fédéral <L foedus, -eris a compact, league]
—fed′er·al·ly adverb

(fed′ər·əl) adjective
1. Of, pertaining to, owned or used by, or representing the United States of America: a Federal building, the Federal Bureau of Investigation.
2. Supporting the Union cause in the American Civil War of 1861–65: the Federal forces.
—noun One who favored or fought for the Union cause in the American Civil War.