a-, an-

(Greek: prefix; no, absence of, without, lack of; not)

These prefixes are normally used with elements of Greek origin, a- is used before consonants and an- is used before vowels.

It affects the meanings of hundreds of words.

There are too many words that use these prefix elements to list all of them on this site; however, there are significant examples listed in this and the other units where they exist.

apterous (adjective) (not comparable)
1. In zoology, descriptive of creatures that have no wings: The biology class planned to visit the apterous section of the local zoo to learn about insects that have no wings.
2. Botany, having no winglike parts or extensions: When Joe planned his garden, he included many apterous plants which would not disseminate their seeds with winglike structures.
apteryx (s) (noun), apteryxes (pl)
Having no wings; especially, the nocturnal wingless and so, flightless, bird of New Zealand having a long neck and a long slender bill, and stout legs: Kiwis are the only surviving apteryx or representatives of the order Apterygiformes.
aptyalia (s) (noun), aptyalias (pl)
The absence of or deficiency in the secretion of saliva: Aptyalias can be caused by disease (mumps, typhoid fever), dehydrations, drugs, radiation therapy to the salivary glands, old age, or the obstruction of salivary ducts.
aptyalism (s) (noun), aptyalisms (pl)
A deficiency or the complete lack of saliva secretion: When Gerald has significant aptyalisms, it becomes very difficult or impossible for him to have enough saliva to moisten his mouth to begin the digestive process, and to lubricate food while he tries to chew and swallow.

Since Martin is afflicted with aptyalism, he has a very dry mouth and has a problem eating without frequent sips of water.

apulmonism (s) (noun), apulmonisms (pl)
The developmental absence of one or both lungs: Arnold was diagnosed with apulmonism when the X-ray revealed that part of one of his lungs was missing.
apyrexia (s) (noun), apyrexias (pl)
The absence or remission of a fever: Dr. Smith was happy to report that Jane had reached a condition of apyrexia.
apyrogenic (adjective), more apyrogenic, most apyrogenic
A reference to ailments that do not cause fevers: Since Wilber had an apyrogenic condition, his sickness was not expected to cause a fever or a pyrogenous problem.
arrhythmia (s) (noun), arrhythmias (pl)
Abnormal rates of muscle contractions or heart movements: With arrhythmias, a person's heartbeats may be too slow, too rapid, or very irregular.

Rapid arrhythmias (greater than 100 beats per minute) are called "tachycardias" while slow arrhythmias (slower than 60 beats per minute) are called "bradycardias"; and sometimes, irregular heart rhythms are called fibrillations or muscular twitching in the heart that involves individual muscle fibers that move without coordination.

asemasia (s) (noun), asemasias (pl)
An inability to understand or to use previously acquired symbols; such as, speech, writing, or gestures, as a means of communication: When Dr. White checked Sidney's inability to use written text or even normal speaking skills, he recognized that Sidney had what was referred to as asemasia in old medical texts.
asemia (s) (noun), asemias (pl)
1. A loss of the ability, previously possessed, to make or understand any sign or signal of communication, whether of organic or emotional origin: Asemias include the trainman's or switch-man's inability to realize the meaning of signals or colored lights, the student's lack of comprehension regarding letters, figures, and mathematical signs and symbols, and the soldier's disregard of bugle calls.
2. The inability to use or to understand signs, gestures, or written or printed language: This disorder of the loss of the ability to make or to understand any of the normal methods of communication is known as asemia which could be caused by a damaged part of the brain or a mental or an emotional problem rather than a physiological ailment.
asepsis (s) (noun), asepses (pl)
1. A condition in which living pathogenic organisms are not present; a state of sterility: Dr. Robinson treated Kirk's wound with an antiseptic so the asepsis would exist there.
2. Free from microorganisms that produce disease, fermentation, or putrefaction: A minimal procedure to ensure one's hands are asepsis is to not only carefully wash them with soap and water, but also to use special alcoholic antiseptics.

Asepsis is a term that is used to distinguish it from "antisepsis" and it applies to the principle in surgery of not applying strong germicides like corrosive sublimate or carbolic acid to wounds.

All of the dressings, swabs, and instruments used in the surgery process are sterilized by steaming, boiling, or dry heat in order to support asepsis.

Asepsis is maintained by using thin, sterilized plastic, or rubber, gloves and gowns with disposable masks which are worn by surgeons to prevent the risk of infection from their hands and wearing apparel.

Surgery that continually utilizes asepsis has the advantage of allowing the germ-destroying activity of the body tissues and their healing powers to increase by not letting antiseptics decrease the vitality of the tissues.

—Compiled from information located in
Black's Medical Dictionary, 35th edition; Edited by C.W.H. Havard;
Barnes & Noble Books; Totowa, New Jersey; 1987; page 58.
aseptic (adjective), more aseptic, most aseptic
1. Free from infection or harmful bacteria; sterile: The medical staff did everything possible to prepare an aseptic condition for Jim's daughter before the surgery took place.
2. The absence of harmful microorganisms: Hospitals are expected to make every effort to keep operating rooms aseptic so patients won’t be contaminated with infectious germs during an operation.
Sterilized and free from germs and harmful bacteria.
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asepticism (s) (noun) (no plural)
1. Free from living germs of disease, fermentation, or putrefaction; sterile: The fermentation barrels were kept in a state of asepticism in order to maintain the high quality and safety of the wine.
2. Designed to prevent infection from pathogenic microorganisms: Ted, the health practitioner, taught the homeless people some basic lessons in asepticism in order to help them maintain better health.
3. Free of pathogenic microbes: An asepticism of surgical instruments and environment is always a major objective of hospitals.
4. Using methods to protect against infection by pathogenic microorganisms: Dr. Payne insists on preparing a condition of asepticism for patients before any surgical procedures take place.
5. Lacking animation or emotion: Jim's facial asepticism was difficult to maintain all the time while the seals were performing at the aquarium.
aseptics (pl) (noun) (used with a singular verb)
1. A product; such as, milk or fruit juice, that is sold in sanitized packages or containers: Jane's grocery list suggested that she should purchase three aseptics; so, she bought milk, a bottle of juice, and a jar of jam.
2. A system of packaging sterilized products in airtight containers so that freshness is preserved for several months: The packaging industry was always looking for ways to increase aseptics in their productions.
asexual (adjective) (not comparable)
1. Without any sexual gestures, feelings, or associations: Hank's friend placed her hand on his shoulder in a friendly, asexual manner.
2. Having no sex; that is, genderless (being neither male nor female): Many organisms, including plants, fungi, parasites, etc., have asexual forms of reproduction.