Cognomen 吉西 (Giese 
, Gysi , 吉西 
) , across the world, is a common family name. The last name 吉西 is characteristic of Switzerland, where it is quite a common surname, Germany, and Denmark, where it is quite a rare surname. Measured by absolute frequency, the name is most common in Germany, the United States, and Switzerland. Very seldom, 吉西 is the forename as well as the last name.