Fed"er*al (?), a. [L. foedus league, treaty, compact; akin to fides faith: cf. F. fédéral. see Faith.] 1. Pertaining to a league or treaty; derived from an agreement or covenant between parties, especially between nations; constituted by a compact between parties, usually governments or their representatives.

The Romans compelled them, contrary to all federal right, . . . to part with Sardinia.

2. Specifically: (a) Composed of states or districts which retain only a subordinate and limited sovereignty, as the Union of the United States, or the Sonderbund of Switzerland. (b) Consisting or pertaining to such a government; as, the Federal Constitution; a Federal officer. (c) Friendly or devoted to such a government; as, the Federal party. see Federalist.

Fed"er*al, n. See Federalist.

• Pertaining to a league or treaty; derived from an agreement or covenant between parties, especially between nations
  
• (USA government): Pertaining to the national government level, as opposed to state, county, city or town
  
• A law-enforcement officer of the FBI.