growth [AS, growan, to grow] , 1. an increase in the size of an organism or any of its parts, as measured in increments of weight, volume, or linear dimensions, that occurs as a result of hyperplasia or hypertrophy. 2. the normal progressive anatomical, physiological development from infancy to adulthood that is the result of gradual and normal processes of accretion and assimilation. The total of the numerous changes that occur during the lifetime of an individual constitutes a dynamic and complex process that involves many interrelated components, notably heredity, environment, nutrition, hygiene, and disease, all of which are subject to a variety of influences. In childhood growth is categorized according to the approximate age at which distinctive physical changes usually appear and at which specific developmental tasks are achieved. Such stages include the prenatal period, infancy, early childhood (including the toddler and the preschool periods), middle childhood, and adolescence. There are two periods of accelerated growth: (1) the first 12 months, in which the infant triples in weight, increases the height at birth by approximately 50%, and undergoes rapid motor, cognitive, and social development; and (2) the second, and the months around puberty, when the child approaches adult height and secondary sexual characteristics emerge. Physical growth may be abnormally accelerated or slowed by a defect in the hypophyseal or pituitary gland. 3. any abnormal localized increase of the size or number of cells, as in a tumor or neoplasm. 4. a proliferation of cells, specifically a bacterial culture or mold. Compare development, differentiation, maturation.
