The 20th letter of the Greek alphabet, transliterated as y or u
Theta Upsilon was created in 1921.
Psi Upsilon was created in 1833.
They are not related.
Theta Upsilon Omega was created in 1924.
Theta Upsilon Omega ended in 1938.
Upsilon Sigma Phi was created in 1918.
Upsilon Pi Epsilon was created in 1967.
Beta Upsilon Chi was created in 1985.
Upsilon Xi was created on 1962-09-26.
Upsilon Andromedae b was created in 1996.
Upsilon Andromedae c was created in 1999.
Upsilon Andromedae d was created in 1999.