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.

anerythroplasia (s) (noun), anerythroplasias (pl)
1. A condition in which there is no formation of red blood cells: More specifically, anerythroplasia is the absence of red blood cell formation in the bone marrow.
2. Etymology: from an-, "not" + erythros, "red" + plasis, "a molding" or "formed".
aneuthanasia (s) (noun), aneuthanasias (pl)
A painful death: Aneuthanasia is a difficult death that occurs with pain and suffering.
anhedonia (s) (noun), anhedonias (pl)
1. Absence of pleasure from the performance of acts that would ordinarily be enjoyable: Saul said that he feared he was suffering from anhedonia because walking in the quiet forest gave him no pleasure.
2. The inability to feel pleasure: Sadie's severe depression brought on a state of anhedonia and she was unable to enjoy any of the things that she once loved to do.
An incapacity for feeling pleasure or happiness.
© ALL rights are reserved.

Go to this Word A Day Revisited Index
so you can see more of Mickey Bach's cartoons.

anhidrosis, anidrosis (s) (noun); anhidroses, anidroses (pl)
1.The deficiency or absence of perspiration or sweating: Grady appeared to have a condition of anhidrosis because he was not sweating even on very hot and humid days.

Dr. Clay told Doyle that it was not a healthy condition to suffer from anhidroses because his skin needed to sweat in order for his body to be healthy.

2. Absence of sweating in horses, a condition more noticeable in hot climates; affected animals develop severe dyspnea (bad breathing) and cannot work: The farmer was concerned because his horses appeared to be ill so Conrad called the veterinarian who told him that they were suffering with anhidrosis.
3. Absence or deficiency of sweating; in humans this is usually due to the absence or paralysis of the sweat glands or to some kind of obstruction of the sweat ducts: When a person experiences anhidrosis, it can be a dangerous health concern.

For some people, having anhidroses may seem to be a blessing; but it isn't, because to sweat makes it possible for us to stay cooler. Anhidrosis creates a dangerous inability for people to tolerate heat.

anhydrase (s) (noun), anhydrases (pl)
An enzyme (protein manufactured by a living cell) that speeds up the rate of reduction or removal of water from a mixture: Jane and Heather were studying the comparative rates of anhydrides from different mixtures or compounds.
anhydration (s) (noun), anhydrations (pl)
A lack of water in the system: After a long hike in the desert, Alfred appeared to be suffering from anhydration and needed to drink lots of water.
anhydride (s) (noun), anhydrides (pl)
A compound derived by the removal of water from an acid or other compound: During the chemistry lesson, Campbell and Joseph experimented with removing water from an acid mixture in order to create other anhydrides or new substances.
anhydrobiosis (s) (noun), anhydrobioses (pl)
1. Dormancy induced by low humidity or by drying out: The seeds of many desert plants go into a state of anhydrobiosis when there is no rainfall for an extended period of time.
2. A state caused by dehydration, in which an organism's metabolism (rate of bodily function) is reduced to an imperceptible level: Dr. Sneed, the veterinarian, was very concerned about the extreme state of anhydrobioses in the dog that was brought into his office because its body processes were barely detectable.
anhydrous (adjective), more anhydrous, most anhydrous
Deprived or destitute of water; without water: Theory speculates that the dinosaurs died off because they lived in an increasingly anhydrous environment.
aniconia (s) (noun), aniconias (pl)
The absence of visual or graphic representation of a god or deity in a religion even when there is no prohibition of such in the religion: The recently discovered religious texts were distinctive as they were aniconias and contained no illustrations of the local deities.  
aniconic (adjective), more aniconic, most aniconic
A description of things that are symbolic or suggestive rather than representing actual deities: Dr. Black, the anthropologist, studied the various anionic objects of worship or their veneration as seen in primitive religions; for example, anionic trees and rocks were symbolic of gods without representing any actual images of them.

Some religions are opposed to the use or presentation of aniconic icons or idols.

aniconism (s) (noun), aniconisms (pl)
1. Opposition to the use of idols or images: Aniconism is a regulation by some religions against the representations of divine creatures.

Among some religious groups, there is a prohibition against aniconism of any images of either living creatures or of any deities.

2. The worship of objects that are symbolic but which do not actually show an image of a god or gods: In the early history of Christianity (726 A.D., Byzantine Emperor Leo 3), there were aniconisms that prohibited the veneration or worship among Christians of any representations of deities.
aniconist (s) (noun), aniconists (pl)
Those who worship such things as trees, rocks, stars, and other natural objects that are symbolic of gods without showing any images of a god or gods: The aniconists of the past, and even in the present times, do not use idols or images of deities to worship.
anisothenic (adjective), more anisothenic, most anisothenic
Characteristic of having unequal strength: As the result of years of carrying the heavy bag of newspapers on Erick's left side during his daily routes, he was aware that he had anisothenic strength in his left arm compared to his more active right arm.
anisotropic (adjective), more anisotropic, most anisotropic
1. A reference to having unequal responses to external stimuli: After Jody's stroke, she exhibited an anisotropic response to physical stimuli on her left side.
2. Having properties that vary depending on the various directions of measurements: A crystal has an anisotropic structure because it is stronger along its length than it is from side to side.
3. Not having properties that are the same in all directions: When measuring the transmission of light through the colored glass, Drew, as a scientist, noted a distinct anisotropic pattern because the properties differed depending on the direction in which he turned the glass.
4. Showing different properties as to velocity of light transmission, conductivity of heat or electricity, compressibility, and so on, in different directions: The early scholars of astronomy noted the anisotropic and varying properties of light, heat, etc. of the stars which they could see.