SOB

SOB is a three-letter abbreviation that can:

in common parlance, a euphemism for "son of a bitch", a general term of abuse.
in medicine, depending on context, stands for "short of breath" or "shortness of breath": see dyspnea.
S.O.B. is a 1981 film written and directed by Blake Edwards.
refers to the a cappella singing group from Yale University that is named the Society of Orpheus & Bacchus.
the distributed computing project Seventeen or Bust
Schweizerische Südostbahn Swiss South Eastern Railway, a private rail company
Small-Of-Back is a type of holster/carry method where the weapon is positioned horizontally at the middle of the back of the carrier's waistband with the grip either pointing straight up or straight down.
an abbreviation for the Seaford Oyster Bay Expressway on Long Island
an abbreviation for the Super Oralloy Bomb, the largest pure fission bomb ever detonated, which had a yield of 500 kilotons.
S.O.B.s is an episode of Arrested Development.
S.O.B. (or SxOxBx) is a Japanese grindcore/death metal band.