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

After world premiering in Cannes‘ Un Certain Regard section, the genre-bending HIV allegory traveled the festival circuit, including stops at Toronto, the AFI Fest and San Sebastián, where it was honored as the best Latin American film. —Georg Szalai, HollywoodReporter, 8 Dec. 2025

Despite making up roughly one-third of the country's population, Black and Hispanic communities account for more than 65% of new HIV diagnoses nationwide—a disparity tied to long-standing inequities in healthcare access, transportation, insurance coverage, and early prevention. —Zachary Bynum, CBS News, 7 Dec. 2025

Those reactions are already rare, Adam Langer, acting principal deputy director and associate director for science at the CDC's National Center for HIV, Viral Hepatitis, STD, and TB Prevention, told the ACIP committee in September. —Madeline Heim, jsonline.com, 5 Dec. 2025

For example, improvements to a biannual injection called lenacapavir could make significant progress toward eliminating deaths from HIV/AIDS, the report said. —Lauren Kent, CNN Money, 4 Dec. 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 (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