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.

abacterial (adjective) (not comparable)
Free of or without microorganisms: After Mary's wound was cleaned by her doctor, it was considered to be an abacterial injury, so it seemed to be in the process of healing very well.
abaptism (s) (noun), abaptisms (pl)
1. The absence of baptism or not having the Christian sacrament that signifies spiritual cleansing and spiritual rebirth: The fact that Gloria's son's abaptism existed when he died was of great concern to his mother.
2. A situation where there is no baptism: The frontier area was often without a pastor and so abaptism usually existed for quite awhile.
abarognosis (s) (noun), abarognoses (pl)
A conscious loss of being able to appreciate the weight of objects held in the hand, or to differentiate objects of different weights: When Sarah went to the grocery store, she found that the abarognosis in her hands made it difficult for her to even estimate how heavy the pineapple she wanted to buy was.

Larry almost dropped the heavy vase that was in his hand because of his abarognosis.

The doctor was not able to determine the cause of Claude's abarognosis or why he couldn't feel the empty glass in his hand.

abasia (s) (noun), abasias (pl)
The inability to walk because of a limitation or absence of muscular coordination which may be a result of psychiatric or physiological origins; unable to walk: Alicia was able to move her legs while she was lying down, but she had abasia when she tried to stand up.
abiocoen, abiocen (s) (noun); abiocoens, abiocens (pl)
The sum of all the nonliving components of an environment or habitat; a nonbiotic habitat: For her master's thesis, Jill studied the abiocoen in a small and defined area.
abiogenesis (s) (noun), abiogeneses (pl)
1. The (supposed) origin or evolution of living organisms from lifeless matter without the action of living parents; spontaneous generation (introduced by Professor Thomas H. Huxley when addressing the British Association at Liverpool, September, 1870): Our professor explained the theory of abiogenesis when we were learning about the evolution of species.
2. The now discredited theory that living organisms can be spontaneously generated directly from nonliving matter: There are conflicts as to whether abiogenesis has any validity.
3. Spontaneous generation; the concept that life can simply arise spontaneously from nonliving matter by natural processes without the intervention of supernatural powers: There have been many throughout history who have strived to disprove the theory of abiogenesis.
abiogenetic (adjective) (not comparable)
Of or pertaining to that which does not result from the activities of living organisms: The former abiogenetic theory that plant and animal life can spontaneously arise from nonliving organic matter in a relatively short period of time has been rejected by just about everyone.
abiogenetically (adverb) (not comparable)
Relating to a condition of not being involved in or produced by living organisms: On TV, the biologists argued about how impractical it would be if any abiogenetically spontaneous existence of life could possibly exist.
abiogenic (adjective) (not comparable)
A reference to creatures not being derived from living organisms and so occurring independently of life or life processes, but perhaps preceding or leading to them: As late as the 17th century, people believed in the spontaneous or abiogenic generation of worms, fish, frogs, and even mice from dew, slime, and mud.
abiogenist (s) (noun), abiogenists (pl)
A person who holds or advocates the hypothesis of the organic phenomenon by which living organisms are created from nonliving matter: There was a whole school of abiogenists during the 17th century who are now the subject of amusement in modern science.
abiogenous (adjective) (not comparable)
Pertaining to the coming into existence without springing from previous living beings: There are those who claim that abiogenous creatures were produced spontaneously without any previous living ancestors.
abiogeny (s) (noun) (no plural)
The origins of living organisms from lifeless matter that does not involve the action of living parents: The biology teacher said that studying biology would be so simple if we could apply the processes of abiogeny as the source of all living creatures.
abiology (s) (noun), abiologies (pl)
1. The study of nonliving or inanimate things: As an alternate to studying biology in school, her son decided to study abiology so he could learn more about inanimate things.
2. The scientific study of things that are not living; in other words, all of the science except those that are biological: Chemistry is an example of one of the abiologies that people have studied.
abiosis (s) (noun), abioses (pl)
1. That which is devoid of life; nonliving: Geology is another example of abiosis or the study of nonliving matter.
2. Anything that is deficient or absent of life: The primary goal of space exploration is to study the abioses of other planets.
abiotic (adjective) (not comparative)
1. A reference to the absence, or deficiency, of life: Is there such a thing as the abiotic existence of matter that is devoid of life or any specific life conditions?

Characterized by the absence of life, inanimate; such as, sand, gravel, stones, etc. all of which are abiotic.

2. Relating to, or caused by, nonliving environmental factors: Many of the abiotic conditions are destructive of living organisms; including temperature, water, soil, pH, and salinity.