Yeah, SD is a "Designer Steroid." Basically it breaks down like this (in general, when being truly accurate about a compound).
Steroids - The old classics, and 99(100?)% of injectibles (black market/perscription only).
Prohormones - Compounds that convert to active steroidal compounds in the body via 1 or more pathways, available OTC.
Designer Steroids - Compounds that are active steroids without conversion, but are sold OTC.