HIV

noun

ˌāch-ˌī-ˈvē 

1

: either of two retroviruses (Lentivirus humimdef1 and L. humimdef2) that infect and destroy helper T cells of the immune system and that when left untreated cause AIDS

Note: HIV retroviruses are transmitted through contact with blood, semen, rectal and vaginal fluids, or breast milk and typically cause flu-like symptoms during the acute phase of infection, but often cause few or no symptoms during the chronic phase of infection when treated with antiretroviral drugs.

… the longer people are infected with HIV and the more immune-deficient they become, the more readily they seem to pass HIV to others.

—Robert R. Redfield et al.

Years of careful research have proven beyond doubt that the HIV virus causes AIDS, that antiretroviral drug treatment saves lives, and that the drug nevirapine is safe and effective in preventing the spread of HIV from mothers to their babies.

—Richard Marlink et al.

called also AIDS virus, human immunodeficiency virus

see also hiv-1, hiv-2

2

: the infection or disease caused by HIV

Early symptoms of HIV develop in 50 to 90 percent of people who are infected, usually beginning two to four weeks after exposure. … Because the signs and symptoms of … HIV may be similar to other common illnesses, such as mononucleosis, most people do not initially realize that they have HIV.

—Paul E. Sax

Examples of HIV in a Sentence

Recent Examples on the Web

Different groups affected by HIV have different needs, and the Jamaican response at the time was generalized, but focused on men who have sex with men. — Jallicia Jolly, Forbes.com, 1 Aug. 2026

In 2015, Strathdee was among a team of researchers to take samples from people with HIV in both Tijuana and San Diego and use the virus’ genetic sequences to understand the geography of transmission. — Eric Boodman, STAT, 31 July 2026

Pregnant people, those with AIDS or HIV and people under 110 pounds may not donate. — Eva Flowe july 30, Charlotte Observer, 30 July 2026

Newman and the team now cater to over 100 various illnesses, including cancer, HIV/AIDS and an array of mental health issues like PTSD and anxiety. — Lily Ford, HollywoodReporter, 29 July 2026

Word History

First Known Use

1986, in the meaning defined at sense 1

Phrases Containing HIV

• anti-HIV

Kids Definition

HIV

noun

ˌāch-ˌī-ˈvē 

: any of a group of viruses that infect and destroy helper T cells causing the marked reduction in their numbers that is diagnostic of AIDS

Medical Definition

HIV

noun

ˌā-ˌchī-ˈvē 

1

: either of two retroviruses (Lentivirus humimdef1 and L. humimdef2) that infect and destroy helper T cells of the immune system and that when left untreated cause AIDS

Note: HIV retroviruses are transmitted through contact with blood, semen, rectal and vaginal fluids, or breast milk and typically cause flu-like symptoms during the acute phase of infection, but often cause few or no symptoms during the chronic phase of infection when treated with antiretroviral drugs.

called also AIDS virus, human immunodeficiency virus

see also hiv-1, hiv-2

2

: the infection or disease caused by HIV