In Boxing, SD is the short term and
type via. Split Decision. In boxing and for other combat sports, a split decision is when 1 of the 3 judges gives it in favour of one fighter. While the rest give the favour to the other fighter.
Split decisions are usually
seen as controversial victories. And many Split decisions can end up overturned and will usually hand a rematch between the two competitors.
There are multiple famous split decision (SD) matches one of them Is in 1987 when Marvin "Marvellous" Hagler fought Sugar
Ray Leonard. and another in 2007 when Oscar De La Hoya fought
Floyd Mayweather being the closest Floyd ever came to a defeat.