Sexual health glossary

Explore each term in this topic, then open its full explanation for context, sources and related reading.

Blood and bodily-fluid exposure
Contact whose infection significance depends on the fluid, route, body site, skin integrity, amount and source context. A splash onto intact skin is not equivalent to a sharps injury or contact with eyes, mouth or broken skin.
Condoms and barriers
Products used to reduce contact with bodily fluids or skin and lower the likelihood of some infections and/or pregnancy. Protection depends on material, fit, correct use and the exposure involved.
Contraception
Methods used to reduce the chance of pregnancy. Methods differ in effectiveness, duration, reversibility, side effects, user control and protection against sexually transmitted infections.
Cross-contamination
Unintended transfer of microorganisms, allergens, irritants or other substances between people, body sites, objects, hands or product containers.
Emergency contraception
Time-sensitive contraception used after sex when no contraception was used or a method may have failed. UK options include a copper intrauterine device and two types of emergency contraceptive pill.
HIV
Human immunodeficiency virus, which affects the immune system. Effective treatment enables long, healthy lives and sustained viral suppression prevents sexual transmission.
Human papillomavirus
A large group of viruses spread mainly through close skin-to-skin sexual contact. Some types cause warts and some high-risk types are linked to cancers.
Lubricants
Products used to reduce friction. Water-, silicone- and oil-based formulations differ in feel, persistence and compatibility with barriers, devices and bodies.
Partner notification
A confidential public-health process that helps people who may have been exposed to an infection obtain appropriate testing, treatment and prevention advice.
PEP
Post-exposure prophylaxis: a time-sensitive course of HIV medicine assessed after a possible exposure to reduce the chance of infection.
Poppers (alkyl nitrites)
A colloquial name for volatile alkyl nitrite products. They can cause brief effects including light-headedness and a fall in blood pressure, but carry important health and medicine-interaction risks. This adult health entry explains significant risks and where to seek help, without instructions for taking or buying these substances.
PrEP
Pre-exposure prophylaxis: prescription medicine used by HIV-negative people to reduce the chance of acquiring HIV when taken or administered as advised.
Sexual health
Physical, emotional, mental and social wellbeing in relation to sexuality—not merely the absence of infection, dysfunction or illness. It includes respectful relationships, safety, pleasure, autonomy, accurate information and access to appropriate care.
Sexual-health clinic
A specialist service providing confidential sexual-health assessment, testing, treatment and prevention. Services may also be called genitourinary medicine, GUM, contraception or integrated sexual-health clinics.
Sexual-health vaccination
Vaccination used to reduce infections relevant to sexual or blood exposure, including HPV and hepatitis B for people eligible under current UK programmes and clinical guidance.
Sexually transmitted infection
An infection that can be transmitted through sexual contact; some can also spread through blood, close skin contact, pregnancy, birth or other routes. Many cause no symptoms.
STI testing and testing windows
Testing for sexually transmitted infections at times and body sites appropriate to the infection, exposure and test. A result obtained too early may not reliably exclude infection.
Undetectable equals untransmittable
The evidence-based principle that a person living with HIV who maintains an undetectable viral load through effective treatment does not sexually transmit HIV.