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 significant examples listed in this and the other units where they exist.
aphydrotaxis, aphydrotactic
1. The absence of a directed response of a motile organism to water.
2. The directed reaction of a motile organism away from moisture.
aphyllous
No leaves; lacking leaves, as most cacti.
aplacental
Without a placenta.
aplasia
1. Complete or partial failure of tissue to grow or develop; arrested development.
2. Defective development or congenital absence of an organ or tissue.
aplastic
Without the power to grow toward normal, healthy tissue.
apleuria
Congenital absence of one or more ribs.
apnea, apnoea
1. Temporary stopping of breathing that occurs in some newborns and in some adults during sleep.
2. Asphyxia.
3. In zoology, a temporary suspension of breathing in hibernating animals.
apneumia
Congenital absence of the lungs.
apodal, apodia
Congenital absence of feet.
apraxia
A loss of the ability to carry out familiar, purposeful movement in the absence of paralysis or other motor or sensory impairments.
aproctia
Congenital absence or imperformation of the anus.
aprosexia
The inability to maintain attention.
aprosodia
The inability to inflect one’s speech with affect or to recognize emotional elements of another’s speech.
aprosody
Absence, in speech, of the normal pitch, rhythm, and variations in stress.
apsychia
Loss of consciousness.
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