HIV

noun

ˌāch-ˌī-ˈvē 

1

: either of two retroviruses (species Human immunodeficiency virus 1 and 2 of the genus Lentivirus) 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

compare 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

Equality California had championed both SB 418 and Assembly Bill 554, which would have required providers to cover antiretroviral drugs to prevent HIV and AIDS. —Lia Russell, Sacbee.com, 14 Oct. 2025

Griffin-Gracy showed up to court hearings and stood in solidarity with young trans people when Arkansas became the first state to outlaw gender-affirming medical care for trans youth in 2021, according to a statement from Chase Strangio, co-director of the ACLU’s LGBTQ & HIV Project. —Nicquel Terry Ellis, CNN Money, 14 Oct. 2025

Popular content creator and comedian Mainly Mannie, born Emmanuel Croxton, has revealed that he’s been diagnosed as HIV positive in an emotional video shared across his social media platforms. —Preezy Brown, VIBE.com, 14 Oct. 2025

The foundation is already working to make cheaper drugs available in lower-income countries, such as by working with Indian drug manufacturer Hetero to bring affordable versions of a new HIV prevention drug for $40 a year. —Alia Shoaib, MSNBC Newsweek, 10 Oct. 2025

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 (species Human immunodeficiency virus 1 and 2 of the genus Lentivirus) 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

compare hiv-1, hiv-2

2

: the infection or disease caused by HIV