AIDS

noun

: a disease of the human immune system that is characterized cytologically especially by reduction in the numbers of CD4-bearing helper T cells to 20 percent or less of normal thereby rendering the subject highly vulnerable to life-threatening conditions (such as Pneumocystis carinii pneumonia) and to some (such as Kaposi's sarcoma) that become life-threatening and that is caused by infection with HIV commonly transmitted in infected blood especially during illicit intravenous drug use and in bodily secretions (such as semen) during sexual intercourse

Examples of AIDS in a Sentence

Recent Examples on the Web
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Gay advocates first began the push for domestic partnerships during the AIDS crisis. Los Angeles Times, 18 Mar. 2026 Yes, that same night, beyond the hallowed walls of Prescott’s, people all across New York were being brutalized by HIV, falling dead from AIDS. Literary Hub, 17 Mar. 2026 Use the proceeds from his drug empire to establish and fund a groundbreaking hospice-care facility in Portland aimed solely at victims of a new disease, AIDS, that was tearing through the country. Jack Crosbie, Rolling Stone, 17 Mar. 2026 For more than 40 years, Sheryl Lee Ralph has been on the frontlines helping raise funds and awareness in the fight against HIV/AIDS. Rance Collins, Variety, 17 Mar. 2026 See All Example Sentences for AIDS

Word History

Etymology

acquired immunodeficiency syndrome

First Known Use

1982, in the meaning defined above

Time Traveler
The first known use of AIDS was in 1982

Cite this Entry

“AIDS.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/AIDS. Accessed 19 Mar. 2026.

Kids Definition

AIDS

noun
: a serious disease of the human immune system marked by destruction of a large proportion of the helper T cells in the body due to infection by the HIV virus commonly transmitted especially in blood and semen

Medical Definition

AIDS

noun
: a disease of the human immune system that is characterized cytologically especially by a reduction in the numbers of CD4-bearing helper T cells to 20 percent or less of normal thereby rendering the subject highly vulnerable to life-threatening conditions (as Pneumocystis carinii pneumonia) and to some that become life threatening (as Kaposi's sarcoma) and that is caused by infection with HIV commonly transmitted in infected blood especially during illicit intravenous drug use and in bodily secretions (as semen) during sexual intercourse

called also acquired immune deficiency syndrome, acquired immunodeficiency syndrome

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