Glossary A-D
Glossary E-I
Glossary R-Z



Kaposi’s Sarcoma (KS)—An AIDS-defining illness consisting of individual cancerous lesions caused by an overgrowth of blood vessels. KS typically appears as pink or purple painless spots or nodules on the surface of the skin or oral cavity. KS also can occur internally, especially in the intestines, lymph nodes and lungs, and in this case is life-threatening. KS frequently occurs in immuno-compromised patients, such as those with AIDS.

Killer Cell—A generalized name for immune system cells that kill cancerous and virus-infected cells. Among the killer cells are killer T-cells (cytotoxic T-lymphocytes), NK (natural killer) cells and K-cells.


Labia—The inner and outer folds of flesh that cover the vagina.

Laser—A powerful beam of light used in some types of surgery to cut or destroy tissue.

Latency—The phenomenon by which disease (such as HSV or HPV) can hide away in the nerve roots in an inactive state, only to reactivate and cause viral shedding or symptoms again.

Lesbian—A woman who is physically and/or emotional attracted is to other women. Some lesbians may prefer to identify as gay or as gay women.

Lesion—A very general term denoting any abnormality on the surface of the body, whether on the skin or on a mucous membrane. Includes sores, wounds, injuries, pimples, tumors, on the skin or elsewhere.

Long-Term Nonprogressor—An individual who has been infected with HIV for at least seven to twelve years (different authors use different timespans) and yet retains a CD4 cell count within the normal range.

Lubricant—A slippery substance. Can be oil- or water-based. A vaginal lubricant may be helpful for women who feel pain during intercourse because of vaginal dryness. If using a lubricant with latex condoms, use one that is water-based, as oil can weaken the latex.

Lymph Node (Lymph Gland)—Small bean-shaped organs made up mostly of lymphocytes, lymph fluid and connective tissue. Clusters of lymph nodes are widely distributed in the body and are essential to the functioning of the immune system. They are connected with each other and other lymphoid tissue by the lymphatic vessels.

Lymphadenopathy—Swelling or enlargement of the lymph nodes due to infection or cancer. The swollen nodes may be palpable or visible from outside the body.

Lymphocyte —White blood cells that mature and reside in the lymphoid organs and are responsible for the acquired immune response. The two major types of lymphocytes are T-cells and B-cells.


MAC (Mycobacterium Avium Complex)—A serious opportunistic infection caused by two similar bacteria found in the soil and dust particles. In AIDS, MAC can spread through the bloodstream to infect lymph nodes, bone marrow, liver, spleen, spinal fluid, lungs and intestinal tract. Typical symptoms of MAC include night sweats, weight loss, fever, fatigue, diarrhea and enlarged spleen. MAC is usually found in people with CD4 counts below 100. MAC is also called MAI (Mycobacterium Intercellulare).

Macrophage—A large scavenger cell that ingests degenerated cells and foreign organisms. Macrophages exist in large numbers throughout the body and contribute to the development of acquired immunity by acting as antigen presenting cells. They also ingest and destroy foreign matter coated with antibody. Macrophages can be infected by HIV.

Maintenance Therapy—Extended drug therapy, usually at a diminished dose, administered after a disease has been brought under control. Maintenance therapy is utilized when a complete cure is not possible, and a disease is likely to recur if therapy is halted.

Malaise—A vague feeling of bodily discomfort and fatigue. This is a common symptom of many illnesses, including many STDs/STIs, and can often be the result of infection or a drug’s side effects.

Malignant —Cancerous; can spread to other parts of the body.

Mammogram—An X-ray of the breast, used to detect breast cancer.

Masturbation—Self-stimulation of the genitals for the purpose of sexual arousal and pleasure.

Memory T-Cell—A T-cell that bears receptors for a specific foreign antigen encountered during a prior infection or vaccination. After an infection or a vaccination, some of the T-cells that participated in the response remain as memory T-cells, which can rapidly mobilize and clone themselves should the same antigen be re-encountered during a second infection at a later time.

Meningitis—An inflammation of the meninges, the protective covering around the brain and spinal cord, usually accompanied by stiff neck and extra sensitivity to light. Septic meningitis, caused by bacteria, can be a serious condition and must be treated immediately. Aseptic meningitis, associated with viral infections such as herpes simplex virus and other causes, generally resolves by itself.

Menopause—Occurs when a woman’s ovaries no longer produce an egg every month and menstruation stops.

Menstruation—The periodic discharge of bloody fluid from the uterus occurring at more or less regular intervals during the life of a woman from age of puberty to menopause.

Metastasis—The spread of cancer from one part of the body to another. Cells that have metastasized are like those in the original (primary) tumor.

Microbe—A microscopic living organism, such as a bacteria, fungus, protozoa or virus.

Moisture barrier—A material, usually latex, used during sexual activity to prevent sexual fluids or blood from passing between people. In addition to condoms for sexual intercourse, moisture barriers for oral sex include household plastic wrap or dental dams.

Mucous Membrane—Moist layer of tissue lining the digestive, respiratory, urinary and reproductive tracts-all the body cavities with openings to the outside world except ears.

Myopathy—Progressive muscle weakness. Myopathy may arise as a toxic reaction to AZT or as a consequence of HIV infection itself.


Neoplasia—Abnormal new growth of cells.

Neurologic—Relating to nervous system, including the brain.

Neuropathy—A disease of the nerves. See Peripheral Neuropathy.

NIAID (National Institute of Allergy and Infectious Diseases)—The federal agency that is responsible for a great deal of the government-sponsored AIDS research. NIAID is a branch of the NIH.

NIH (National Institutes of Health)—The federal agency responsible for overseeing government-sponsored biomedical research. It is divided into 24 institutes and research centers.


Obstetrician-Gynecologist—A physician with special skills, training and education in women’s health.

Ocular herpes—Herpes infection in the eyes.

Off-Label—Use of a drug for a disease or condition other than the indication for which it was approved by the FDA. For example, many doctors prescribe paromomycin (humatin) for cryptosporidiosis, although it is not approved for treating this disease.

Oncologist—A doctor who specializes in treating cancer.

Opportunistic Infections (OI)—Infections that occur in persons with weak immune systems due to AIDS, cancer or immunosuppressive drugs such as corticosteroids or chemotherapy. PCP, toxoplasmosis and cytomegalovirus are all examples of OIs.

Oral-facial herpes—The presence of latent herpes simplex infection in the trigeminal ganglion, located at the top of the spine. When reactiviated, oral-facial herpes can cause symptoms anywhere on mouth or face—typically cold sores on the lips. Recurrent oral-facial herpes is largely caused by HSV-1.

Orgasm—Sexual climax.

Ovaries —The pair of female reproductive glands in which the ova, or eggs are formed. The ovaries are located in the lower abdomen, one on each side of the uterus.

Pap Test—A test done to examine cells collected from the cervix and vagina. This test can show the presence of infection, inflammation, abnormal cells, or cancer.

Papule—A small elevation or bump on the skin.

Pathologist—A doctor who identifies diseases by studying cells and tissues under a microscope.

PCP (Pneumocystis Carinii Pneumonia)—A pneumonia caused by an infection with Pneumocystis carinii. P. carinii grows rapidly in the lungs of people with AIDS and is the leading AIDS-related cause of death. P. carinii infection sometimes may occur elsewhere in the body (skin, eye, spleen, liver or heart). There are inexpensive drugs that can prevent and treat PCP.

PCR (Polymerase Chain Reaction) Test—A very sensitive test that measures the presence or amount of RNA or DNA of a specific organism or virus (for example, HIV or CMV) in the blood or tissue.

Pelvis—The lower part of the abdomen between the hip bones. Organs in a female’s pelvis include the uterus, vagina, ovaries, fallopian tubes, bladder, and rectum.

Penile cancer—Cancer of the penis. A malignant growth of cells in the tissue and/or external area of the penis. Rare in most industrialized nations, it is an aggressive form of cancer occurring primarily in older men.

Perinatal Transmission—Transmission of a pathogen, such as HIV, from mother to baby during birth.

Peripheral Neuropathy—A condition characterized by sensory loss, pain, muscle weakness and wasting of muscle in the hands or legs and feet. In severe cases, paralysis may result. Peripheral neuropathy may arise from an HIV-related condition or be the side effect of certain drugs.

Phimosis (and paraphimosis)—Phimosis is a condition created when a man has an extremely tight foreskin. Paraphimosis is a less common, but more serious, version of phimosis in which the foreskin is so tight that it can cut off blood flow once it is pulled back behind the glans (head) of the penis.

Pneumocystis Carinii Pneumonia—See PCP.

Polymerase Chain Reaction—See PCR.

Primary HIV Infection—The flu-like syndrome that occurs immediately after a person contracts HIV. This initial infection precedes seroconversion and is characterized by fever, sore throat, headache, skin rash and swollen glands. Also called acute infection.

Prodrome—An early warning symptom of illness. (i.e., prodrome for a genital herpes outbreak often involves an aching, burning, itching, or tingling sensation in the genital area, buttocks, or legs).

Prodrug—A compound that must undergo chemical conversion within the body to change to its active form that has medical effects. Prodrugs are useful when the active drug may be too toxic to administer systemically, the active drug is absorbed poorly by the digestive tract, or the body breaks down the active drug before it reaches its target.

Prognosis—The probable outcome or future course of disease in a patient; the chance of recovery.

Prophylaxis—Treatment to prevent the onset of a particular disease (“primary” prophylaxis) or recurrence of symptoms in an existing infection that has been brought under control (“secondary” prophylaxis, or maintenance therapy).

Protease—An enzyme that triggers the breakdown of proteins. HIV’s protease enzyme breaks apart long strands of viral protein into the separate proteins making up viral core. The enzyme acts as new virus particles are budding off a cell membrane.

Protease Inhibitor—A drug that binds to and blocks HIV protease from working, thus preventing the production of new infectious viral particles.

Pubic lice—Pubic lice, also called “crabs,” are small parasites that feed on human blood. Pubic lice are not the same as head and body lice. Pubic lice are usually found on the pubic hair, but can be also be found on other parts of the body where a person has coarse hair (such as armpits, eyelashes, and facial hair). Most cases of crabs are transmitted through sexual contact, when the crabs move from the pubic hair of one person to the pubic hair of another.