"The terminology used to describe older persons varies considerably, even in international documents," a United Nations report says. "It includes: 'older persons,' 'the aged,' 'the elderly,' 'the third age,' 'the ageing,' and, to denote persons more than 80 years of age, 'the fourth age.' The committee opted for 'older persons' (in French, personnes âgées; in Spanish, personas mayores), the term employed in General Assembly resolutions 47/5 and 48/98." In the United Nations' statistical services, these terms cover people older than 60. The statistical service of the European Union considers "older persons" to mean people aged 65 or above, because 65 is the most common age of retirement and the trend is towards later retirement still.
See United Nations Committee on Economic, Social and Cultural Rights. The economic, social and cultural rights of older persons. Geneva: UN High Commissioner for Human Rights, 1995 and BMJ 2007;334:316, doi:10.1136/bmj.39111.694884.94.
Thanks to Margaret Cooter