Height (redirected from 3rd dimension)

height

Astronomy the angular distance of a celestial body above the horizon

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height [hīt]

(mathematics)

The perpendicular distance between horizontal lines or planes passing through the top and bottom of an object.

The height of a rational numberqis the maximum of |m| and |n| , wheremandnare relatively prime integers such thatq = m/n.

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height

1. The distance between two points aligned vertically.

2. In buildings, the distance vertically from the average grade at front sides and/or rear of a building (or the average elevation of the curb or curbs of the streets faced by the building) to the average level of the roof.

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Height 

(body length), the measurement of a person from the apical point of the head to the bottom of the feet. Height is one of the most important body dimensions and, together with other features, characterizes physical development, body proportions, morphological status and, on a broad scale, ethnic group.

A function of external environmental and hereditary factors, height varies according to age, sex, and ethnic group, as well as the individual and the epoch. Body length does not increase at a uniform rate during different periods of growth. Growth rates are highest during the uterine period. The length of boys and girls at birth averages 51.5 and 51 cm, respectively.

There are three phases of change in annual increase of height: the rate of annual increase diminishes from birth to puberty, increases or becomes stabilized during puberty, and decreases thereafter. The increase in body length during the first year of life is 24 cm. Until three years of age the annual increase is 10 cm, and from three to seven years of age it is 6–6.5 cm. During puberty, height increases 5–7 cm a year. Because girls mature earlier than boys, they grow more rapidly between the ages of ten and 14 and surpass boys in height, but after 14, boys again become taller. Growth generally ends in males between the ages of 18 and 20 and in females between 16 and 18. Mature females are 8–11 cm shorter than males. In the USSR, for example, the average height of males and females in the 1960’s and 1970’s was 167–168 and 156–157 cm, respectively.

After growth ceases and until about 50 years of age, height is stable, after which it gradually decreases because of the aging process. During the growth phases there are variations according to social strata and ethnogeographic groups. For example, the increase in growth during puberty and the cessation of growth occur later in rural areas than in the city. In areas where socioeconomic differences are pronounced, persons who are financially better off are usually taller than those who are not.

Ethnogeographic differences in height are not always related to geography and climate. For example, Eskimos, Buriats, and Vietnamese are short (males are less than 160 cm tall), whereas Scots, Swedes, and inhabitants of the Balkan peninsula are tall (over 170 cm). The Bambuti pygmies of the Congo River basin are 144 cm tall, while members of the Tutsi tribe in neighboring Rwanda are 176.5 cm tall.

The range of individual variations in height is greater than the range of group variations—± 18–20 cm from the arithmetic mean height of a given group. Height in males that is less than 125 cm is called dwarfism, and height more than 200 cm gigantism. Epochal changes in height are manifested by acceleration.

V. S. SOLOVEVA