Prefixes: a- and an- of English words
Part 1 of 4.
“abacterial” to “alexia”
a-, an- (Greek: a prefix meaning: 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 some significant examples listed in this and the other groups provided.
abacterial:
Free of bacteria; without bacteria.
abaptism:
The absence of baptism; no baptism.
abarognosis:
Loss of the sense of weight; unaware of weight.
abasia:
The inability to walk due to a limitation or absence of muscular coordination; not able to walk.
abiocoen, abiocen:
The sum of all the nonliving components of an environment or habitat.
abiogenesis: [ab" ee oh JEN uh sis, ay" bigh oh JEN uh sis]
1. The origin of living things from things inanimate; i.e., life coming from non-living material.
2. Spontaneous generation; the concept that life can slimply arise spontaneously from non-living matter by natural processes without the intervention of supernatural powers.
abiology:
The study of non-living things.
abiosis, abiotic:
Absence or deficiency of life; devoid of life.
abiotrophy:
Progressive loss of vitality of certain tissues or organs leading to disorders or loss of function. The longevity of the heart, for instance, may be appreciably shorter than that of other organs of the body, leading to early disturbance in function which upsets organ-equilibrium.
ablepsia:
Loss of sight; blindness.
abrachia:
Congenital absence of arms; having no arms.
abranchiate:
Without gills.
abrosia:
The total lack of food consumption; fasting.
abulia, abulic:
1. Absence of willpower or wishpower; the term implies that the subject has a desire to do something but the desire is without power or energy.
2. A disorder marked by the partial or total inability to make decisions.
abysm, abyss:
Without a bottom; bottomless.
abysmal:
Not capable of being measured or understood; incomprehensible, inscrutable.
acapnia:
Lack of carbon dioxide in the blood and tissues.
acardia:
Without a heart; having no heart.
acarpous:
Without fruit, not bearing fruit.
acathisia:
The inability to sit down because of the intense anxiety provoked by the thought of doing so. It may also apply to the inability to sit still and to other irritative, hyperkinetic symptoms that are sometimes seen as a complication of neuroleptic therapy.
acathexia:
Inability to retain bodily secretions.
acaudal, acaudate:
Without a tail; tailess.
acaulescent:
With no stem or with a stem that is very short.
acellular:
Containing no cells.
acenesthesia:
Absence of the normal sense of physical existence and well-being and of the regular functioning of the bodily organs.
acentric:
Not central; not located in the center.
acephalia, acephalous:
1. The absence of a head; having no head.
2. Having no leader or ruler.
acephalobrachia:
Congenital absence of the head and arms.
acephalochiria:
Congenital absence of the head and hands.
acheilia:
A condition present at birth in which there is an absence of one or both lips.
Part 2
acheiria, achiria:
Lacking hands; also, loss of sensation, total anesthesia, or a feeling of absence of the hands; sometimes a hysterical symptom.
acheiropody:
Absence of the hands and feet.
achondroplasia:
A congenital bone disorder caused by abnormal conversion of cartilage into bone, resulting in deformities and dwarfism.
achromatic, achromic:
Without color; unpigmented; white, gray, or black in appearance.
acinesia:
Lack of movement.
aclusion:
Absence of occlusion of the opposing tooth surfaces.
acoprosis:
Absence of fecal matter from the intestine.
acoprous:
Having no fecal matter in the intestine.
acoria:
Absence of the pupil of the eye.
acotyledon:
Any plant without seed leaves.
acrania:
A partial or complete absence of the skull.
acroagnosia:
Lack of sensory recognition of a limb.
adactyly, adactylia:
The absence of digits on the hand or foot.
adermia:
Without skin.
adiabatic:
In thermodynamics, describing a process in which there is no transfer of heat into or out of the system in question; without loss or gain of heat.
adiadochocinesia, adiadochocinesis; adiadochokinesia, adia-
dochokinesis:
Loss of the power to perform rapid alternating movements. This symptom is indicative of a disorder of the cerebellum or its tracts.
adiaphoria:
Non response to stimuli as a result of some previous exposure to similar stimuli.
adiathermancy, adiathermance:
The condition of being impervious to or unaffected by heat waves.
adiathermanous, adiathermic:
In physics, a reference to the inability of transmitting radiant heat; not affected by heat.
adipsia:
The abnormal absence of thirst; an abnormal avoidance of drinking.
adromia:
The absence of impulse conduction in a nerve of a muscle.
adynamia, adynamic:
1. Lack or loss of normal or vital powers.
2. Characterized by or causing weakness.
afebrile:
Without fever.
afetal:
Without a fetus.
agalactia:
Absence of milk in the breasts after childbirth.
agamete:
An asexual reproductive cell that progresses directly into an adult, as a spore.
agamic:
Nonsexual reproduction, as by fission, budding, etc.
agastria:
Absence of the stomach.
agastric:
Having no alimentary canal.
agenesis:
Lack of development or absence of an organ or other body part.
ageotropism, ageotropic:
The absence of orientation movements in response to gravity.
agerasia:
Without old age; appearance of youth in old age.
ageusia, ageustia:
Absence or impairment of the sense of taste; it may be due to disorder in the gustatory apparatus (i.e. the taste buds). It is also seen in psychiatric conditions, particularly in depressed patients who complain that food is tasteless.
aglossia:
Without a tongue; not tongue.
agnathia:
A total absence of the lower jaw.
agnosia:
1. The inability to recognize certain sensory stimuli.
2. A loss of the ability to comprehend the meaning or to recognize the importance of various types of stimulation.
3. Total or partial loss of the ability to recognize familiar objects, often resulting from brain damage.
agnostic:
1. Not known, unknown; [coined by Thomas Huxley in 1870]; an assertion of the uncertainty of all claims to knowledge.
2. One who believes the existence of God is unknown, but does not deny the possibility that God exists.
Part 3
agonic:
Not forming an angle; no angle.
agrammaphasia:
Ungrammatical speech; a form of aphasia, in which the patient forms words into a sentence without regard for grammatical rules of declension, conjugation, comparison of adjectives and adverbs, auxiliary verbs, prepositions, conjunctions, articles, etc.
agrapha:
Sayings attributed to Jesus, but not in the Bible.
agraphia:
A disorder marked by the inability to write; loss of the power, or the inability, to communicate (ideas) in writing, and thus a subdivision of aphasia.
agraphognosia:
The inability to identify numbers or letters traced on the palm (or other parts of the body surface).
akinesia, akinesis:
1. Absence or poverty of movements.
2. Absence or diminution of voluntary motion that may range from moderate inactivity to almost complete immobility.
alalia:
Speechlessness; loss of the ability to talk.
aleukemia:
A lack of leukocytes in the blood.
aleukocytic:
Absence or extremely reduced numbers of leukocytes in the blood or in lesions.
alexia:
1. A loss of the ability to understand written language, inability to read because of brain lesions; word blindness.
2. An acquired disorder in reading ability; to be differentiated from dyslexia, which is a developmental problem in reading. [Strictly speaking, lexus and its derivatives refer to speech, not reading, because they are based on the Greek verb legein, to speak, and not on the Latin verb legere, to read. Current usage appears to reflect an etymological error, so long accepted that to insist on correcting it would be useless.]
—Psychiatric Dictionary, 7th Ed., Robert J. Campbell, M.D.;
Oxford University Press, 1996; New York.
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