Senescence

n. aging process, process of growing older

In biology, senescence is the combination of processes of deterioration which follow the period of development of an organism. For the science of the care of the elderly, see gerontology; for experimental gerontology, see life extension. The word senescence is derived from the Latin word senex, meaning "old man" or "old age."
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Noun
1. the organic process of growing older and showing the effects of increasing age
(synonym) aging, ageing
(hypernym) organic process, biological process
(hyponym) catabiosis
2. the property characteristic of old age
(synonym) agedness
(hypernym) oldness

n. senescence, aging process, process of growing older

(n.)
The state of growing old; decay by time.