What does 3-D stand for?

Decapitation, Disembowelment, and Dismemberment [Types of movies]

Selective Service Class [for Man Deferred from Military Service Because Induction Would Cause Extreme Hardship and Privation to a Wife, Child, or Parent] [Obsolete]

Three-Dimensional [Pictures or films]

Triple-Diffusion Process (MDG)

Delayed Double Diffusion [Test] (DAVI)

Swaziland [Aircraft nationality and registration mark] (FAAC)

Third Down [Football]

Three Times a Day [Medicine] (MELL)