HIV - Human immunodeficiency virus is a virus that causes acquired immunodeficiency syndrome (AIDS), a condition in which the immune system begins to fail, leading to life-threatening infections.

AIDS - It means "Acquired immune deficiency syndrome", represents a disease of the human immune system caused by the HIV. The condition progressively reduces the defence of the immune system and leaves the individual vulnerable to other infections.

HIV-positive - A person infected with HIV.

Vulnerability - Weakness towards infections.

Transmission route - Physical way for transmission of a disease, for example through the air, the bloodstream, or by saliva.

Stigma - Refers to prejudice, negative attitudes, abuse, maltreatment and discrimination towards HIV-positives.
Literally it means that a person is "marked", so he/she is different from the others in some way.

HIV prevention - A set of measures that an individual could take to eliminate or lower the risk of infection with HIV. They include knowing the ways of contamination, safety precautions(using a condom; having sex with less partners), medical threatment and  basic knowledge on the topic of HIV/AIDS.

Antiretroviral treatment - A treatment towards retroviruses.

Retrovirus - RNA virus that is replicated in a host cell via the enzyme "reverse transcriptase" to produce DNA from its RNA genome.

Ostracism - A form of discrimination, prohibiting residence in a specific place for a period of time.

Pandemic -  Infection among the population in huge areas, for example continents.

Young People - Young people are persons 13 – 30 years old (for the purposes of European youth policies this age is used both by the European Commission and Council of Europe).

Young people with fewer opportunities are young people from a less-privileged cultural, geographical or socio-economic background, or with disabilities.