Initialism of sudden-onset explosive diarrhea.

Initialism of Shorter Oxford English Dictionary.

The conventional Morse code call made by a ship in distress.

(games) A children's game in which players take turns to place S's and O's on a grid, collecting points by creating an "SOS" sequence.

plural of so

(idiomatic) Up to this point, all is OK.

Even; suggests a minimum, especially regarding what might be expected. / But rather.

Isn't it true? / Isn't it that way?

plural of SO-DIMM

Apparently, according to others.