Grössencharakter

In the original formulation, a quantity associated with ideal class groups. According to Chevalley's formulation, a Grossencharacter is a Multiplicative Character of the group of Adéles that is trivial on the diagonally embedded $k^\times$, where $k$ is a Number Field.

References

Knapp, A. W. ``Group Representations and Harmonic Analysis, Part II.'' Not. Amer. Math. Soc. 43, 537-549, 1996.