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.

asynergy (s) (noun), asynergies (pl)
Lack of coordination among various muscle groups during the performance of complex movements, resulting in a loss of skill and speed: During the swimming match, Karen's friend experienced a moment of asynergy which caused her to lose speed and resulted in her not being able to perform at her best.
asynesia (s) (noun), asynesias (pl)
Mental dullness; ignorance, or a lack of practical understanding and comprehension: Blanche's state of asynesia makes it difficult for her to understand simple and practical instructions.
asyntaxia (s) (noun), asyntaxias (pl)
A situation characterized by a lack of typical or orderly embryonic development: The research project at the veterinarian school was directed at understanding the asyntaxia of specific bovines including cows and bulls.
asystole (s) (noun), asystoles (pl)
A fatal cardiac condition characterized by the absence of a heartbeat: The unexpected death of Mr. Anderson, the medical officer, was attributed to his asystole.
asystolia (s) (noun), asystolias (pl)
A halt in the pumping action of the heart caused by a cessation of its rhythmic, muscular functions: A person with asystolia collapses suddenly, with a loss of consciousness, absence of pulse, and no breathing.
asystolic (adjective), more asystolic, most asystolic
A reference to the absence of a heartbeat or descriptive of a cardiac arrest: The emergency paramedics responded to Hazel's systolic condition by rushing her to the cardiac ward at the local hospital.
atactic (adjective), more atactic, most atactic
A reference to the lack of motor coordination or the loss of the ability to coordinate muscular movements: Jake's friend developed an atactic walk after a serious accident and was no longer able to walk in a normal way without moving sideways to the left or to the right.
atactiform (s) (noun), atactiforms (pl)
A condition in which a person is unable to control or to moderate his or her body movements because of the failure of muscular coordinations and irregularity of muscular activities: The doctor informed June that her neurological condition was progressive and she would experience additional atactiforms in the future.
atactilia (s) (noun), atactilias (pl)
A condition in which a person experiences a loss of the sense of touch or feeling: George was reassured that the atactilia which he was experiencing was transitory and temporary and so it would not last much longer.
ataractic (adjective), more ataractic, most ataractic
Relating to a drug or other agent that has a calming effect: Dr. Jones said the ataractic prescription would soothe and tranquilize the tensions and stresses that Ted was having as a result of his overworking and not getting enough sleep.
ataraxia (s) (noun), ataraxias (pl)
1. The absence of anxiety or confusion: The spiritual guru was an outstanding example of ataraxia as he showed a sense of calmness and inner harmony.
2. A tranquilizer that has a calming effect: Because Jimmy was having difficulty sleeping, his mother asked the doctor to prescribe an ataraxia to help him relax so he could go to sleep and get some rest.
ataxaphasia (s) (noun), ataxaphasias (pl)
An inability to form phrases and sentences despite the ability to enunciate individual words: Communication for Mitchell, the wounded soldier, was difficult because of the ataxaphasias he was experiencing during which he was able to say individual words but he wasn't able to combine them into normal sentences.
ataxia (s) (noun), ataxias (pl)
1. Absence or lack of order; lack of coordination: Meg's cousin always refused to dance because of her sense of ataxia and feeling as if she had two left feet.
2. The inability of someone to be physically able to perform complex moves during muscle activity while making voluntary movements or when doing irregular muscular actions: Swimming proved to be difficult for Harriet's sister because of her ataxia and inability to move her arms and legs in coordinated and sequential movements.
3. Unsteadiness, incoordination or disorganization of movements in the absence of paralysis: For a few moments after getting off the Merry-Go-Round, Billy looked as if he were experiencing ataxia because he was staggering with dizziness and walking in an uncoordinated way.
ataxiadynamia, ataxoadynamia (s) (noun); ataxiadynamia, ataxoadynamias (pl)
Muscular weakness combined with incoordination: The progressive neurological condition that Mark was was experiencing is characterized by ataxiadynamia which may be caused by damage to the cerebellum or that part of the brain which is responsible for the coordination of complex voluntary muscular movements as well as the maintenance of posture and balance.
ataxic (adjective), more ataxic, most ataxic
A reference to a lack of motor coordination: While performing voluntary movements, Mary's ataxic style of walking appeared to be clumsy and unstable.