TSD can refer to different things depending on the context. Here are some possible meanings:

• Tactical Sperm Dump: According to Urban Dictionary, this acronym stands for "tactical sperm dump". It refers to when a man masturbates shortly before having sex with a female friend so that he can last longer during intercourse.

• Tay-Sachs Disease: According to RxList and Better Health Channel, TSD is an abbreviation for Tay-Sachs disease, a genetic metabolic disorder that affects the nervous system. Symptoms usually first appear at around six months of age in a previously healthy baby, and the condition becomes progressively worse over time. Tay-Sachs disease is most commonly observed in individuals of Jewish and French-Canadian descent, but can also occur in people from other backgrounds.

• Other meanings: TSD can also stand for other things, such as Tactical Surveillance Demonstration, Traffic Situation Display, Transportation Safeguards Division, Therapeutic Shock Device, Therapeutic Sleep Deprivation, Thermionic Specific Detection, or Three-System Disease. However, without additional context, it is impossible to determine which meaning is intended.