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"development of an individual," 1872, from onto- + -geny. Related: Ontogenic; ontogenesis.
ontogenesis on·to·gen·e·sis (ŏn'tō-jěn'ĭ-sĭs)n. See ontogeny.
ontogeny on·tog·e·ny (ŏn-tŏj'ə-nē)n. The origin and development of an individual organism from embryo to adult. Also called ontogenesis.