An abbreviation for the instance "Scarlet Monastery", a dungeon in the game World of Warcraft. Usually used by player looking for people to group with. The instance is separated into four parts, the Library, the Armory, the Graveyard, and the Cathedral.

Abbreviation for Saint Morning, a town in the online game Flyff.

Service Mark.

TM (Trademark) is always recommended over SM.

Self mutilation. When someone physically injures themselves to rid or relieve themselves of mental pain.

A highly addictive practice, as when the body is physically injured it releases endorphins into your brain and blocks mental stress. Similar to the "high" you get after virgerous excercise.

Just because you sm doesn't mean that you are suicidal, or have any wish to die whatsoever.

SM obviously has as the most prominent meaning sado masochism. But it can also be used by people to say 'single mother'