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

Many are older adults living with HIV, hepatitis, cancer, liver disease or multiple chronic conditions. —Scott Suckow, San Diego Union-Tribune, 4 Mar. 2026

Panel's impact on health coverage The 40-year-old USPSTF is responsible for deciding which medical tests and treatments, such as routine breast cancer screening or drugs to prevent HIV infection, need to be provided cost-free under most health insurance plans. —Reuters, NBC news, 4 Mar. 2026

Before that, Levy served as executive director of a statewide advocacy organization focused on improving health equity for LGBTQ communities and people living with HIV. —Nora O'Neill, Charlotte Observer, 4 Mar. 2026

Seven people have been declared HIV-free after receiving a stem cell transplant – and, significantly, two of them had received stem cells that were not actually HIV-resistant. —Harriet Marsden, TheWeek, 3 Mar. 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