U 21
U 21 , U21 or U-21 stands for:
- an age group in sport, see class division in sport
- U-21 national team
- Subway line 21 (Nuremberg) (part of the subway line 2)
U 21 is the name of the following submarines:
- SM U 21 (1913–1919), a submarine of the German Imperial Navy
- U 21 (kuk Marine) (1916–1919), a submarine of the Austro-Hungarian Navy
- U 21 (Kriegsmarine) (1936–1944), a submarine of the German Kriegsmarine
- U 21 (Bundeswehr) (1974–1998), a submarine of the German Navy
See also:
- Submarine class XXI (Type 21)
