STD = Subscriber Trunk Dialling. It helps whilst making national (as opposed to local) calls.
What Is The Full Form Of STD?
The Full Form of STD is 'Subscriber Trunk Dialing'.
It can also stands for Sexually Transmitted Disease. An STD can be spread most commonly from unprotected sex. There are many different diseases that are classed as STD's. This includes Gonorrhoea, Syphilis, Chlamydia, Hepatitis A B and C, Non Specific Urethritis (NSU), Herpes and Genital Warts.
Standard Trunk Dialing or Sexually Transmitted Disease