Ageing or aging (see spelling differences) is the process of becoming older. ... In the broader sense, ageing can refer to single cells within an organism which have ceased dividing (cellular senescence) or to the population of a species (population ageing).
Old age, also called senescence, in human beings, the final stage of the normal life span. ... For statistical and public administrative purposes, however, old age is frequently defined as 60 or 65 years of age or older.
