STD

sexually transmitted disease (STD)

Disease transmitted primarily by direct sexual contact. STDs usually affect the reproductive system and urinary system but can be spread to the mouth or rectum by oral or anal sex. In later stages they may attack other organs and systems. The best-known are syphilis, gonorrhea, AIDS, and herpes simplex. Yeast infections (see candida) produce a thick, whitish vaginal discharge and genital irritation and itch in women and sometimes irritation of the penis in men. Crab louse infestation (see louse, human) can also be considered an STD. The incidence of STDs has been affected by such factors as antibiotics, birth-control methods, and changes in sexual behaviour. See also chlamydia; hepatitis; pelvic inflammatory disease; wart.

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STD

(Subscriber Trunk Dialing) Long distance dialing outside of the U.S. that does not require operator intervention. STD prefix codes are required and billing is based on call units, which are a fixed amount of money in the currency of that country. For example, one call unit may be charged for establishing the call, and each call unit pays for some amount of time depending on the distance between parties.

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STD

(medicine)

sexually transmitted disease

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STD

On drawings, abbr. for standard.

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1.		STD - state transition diagram.
2.		STD - Internet standard. A subseries of Request For Comments (RFC) that specify Internet standards. The official list of Internet standards is STD 1. See also For Your Information. rfc.net.