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a. a period of history marked by some feature or characteristic; era
b. (capital when part of a name): the Middle Ages; the Space Age
2. Geology palaeontol
a. a period of the earth's history distinguished by special characteristics
b. the period during which a stage of rock strata is formed; a subdivision of an epoch
3. Myth any of the successive periods in the legendary history of man, which were, according to Hesiod, the golden, silver, bronze, heroic, and iron ages
4. Psychol the level in years that a person has reached in any area of development, such as mental or emotional, compared with the normal level for his chronological age
5. of age adult and legally responsible for one's actions (usually at 18 or, formerly, 21 years)



in humans, a stage of development that is characterized by specific regularities of formation of the organism and personality and by relatively stable morphophysiological and psychological traits. While age is a stage in the biological maturing of the organism, a process controlled by genetic factors, it is also a concrete result and stage of the social-psychological development of the personality and is determined by the conditions of life, training, and upbringing.

The content and form of training and upbringing are historically composed and varied according to age; in their turn they affect the determination of the boundaries and possibilities of a given age. In contemporary pedagogy and developmental psychology, several ages are differentiated with respect to the known relationships of the boundaries: infancy (from birth to one year); pre-preschool, or early childhood (from one to three); preschool (from three to seven); early school age (from seven to ten years); juvenile, or middle school (from ten to 15); and late school, or early youth (15 to 18 years old). Beyond these limits there is no generally accepted classification in the literature; only old age is considered separately. With the increased longevity noted in the 20th century, gerontology and gerontopsychology have arisen as disciplines to study the problems of prolonging the active life of a human being. Each age has a characteristic structure of cognitive, emotional, and volitional properties and qualities; forms of behavior; types of relationships to the environment; and peculiarities of structure and functioning of various organs and systems of the organism. This structure, however, is not invariable: in the 20th century a general acceleration of the physical and mental development of children has been noted. On the other hand, educational theory, in solving the problem of optimizing training, widens the possibilities of age and the boundaries of acquiring knowledge. Training must take into account not only the level of development achieved but also the development perspectives (the concept of “zones of imminent development,” as formulated by L. S. Vygotskii): the teacher must know not only what is present in a child of a given age but also what can be achieved, given certain conditions, by the child in the near future.



Period of time from origin or birth to a later time designated or understood; length of existence.
Any one of the named epochs in the history of the earth marked by specific phases of physical conditions or organic evolution, such as the Age of Mammals.
One of the smaller subdivisions of the epoch as geologic time, corresponding to the stage or the formation, such as the Lockport Age in the Niagara Epoch.


(aerospace engineering)
References in periodicals archive ?
The aim of the study was to find out the different types of diabetes and their epidemiology and also to study the clinical abnormalities like age of onset, age/sex ratio, urban/rural difference, clinical symptoms and complications in adolescents and young diabetic patients getting treatment from our institution.
There were significant differences in gender, age, total duration of illness, age of onset, the dose of antipsychotic medication (daily chlorpromazine equivalent), negative symptom factor scores and the total PANSS scores between the TD group and non-TD group.
Though the mean DLQI differed between groups among gender, age, occupation, age of onset and duration, the difference was not statistically significant.
Statistical analyses showed no correlations between size of mtDNA deletions and age of onset ( P = 0.
05) early age of onset was in genetically predisposed group when compared to the non-genetically predisposed group.
This is close to the ranges seen in the North Indian study8 where the peak age of onset in boys was in the 6-10 years age group, whereas the majority of the girls showed onset of psoriasis between the ages of 10 and 14 years.
This patient (Table 1, patient 4) had an age of onset of 50 years with no family history of the disorder.
When the age of onset of the disease was observed, it was found to range between 10 and 63 years, whereas the mean age of onset was 34.
For women in midlife, an earlier age of onset of vasomotor symptoms--hot flashes and night sweats--was linked to impaired endothelial function, a very early marker for cardiovascular disease.
Subject entries include acrophobia, age of onset, cognitive bias modification, comorbidity, three pathways theory, and a wide variety of other related topics.
The study revealed a marked increase in the prevalence of dementia for people with Down syndrome, in comparison to the general ageing population, with the average age of onset 55, compared to 65 in the general population.
The Study: The age of onset of body hair growth, voice deepening and facial hair growth was determined for 3,199 boys.