Ageism, also spelled agism, is stereotyping and/or discrimination against individuals or groups on the basis of their age. This may be casual or systemic.[1][2] The term was coined in 1969 by Robert Neil Butler to describe discrimination against seniors, and patterned on sexism and racism.[3] Butler defined "ageism" as a combination of three connected elements. Originally it was identified chiefly towards older people, old age, and the aging process; discriminatory practices against older people; and institutional practices and policies that perpetuate stereotypes about elderly people.[4]

Robert N. Butler coined the term "ageism" in 1969

Although in the UK it was used (March 1983) in terms of discrimination against younger people by Councillor Richard Thomas at a meeting of Bracknell Forest Council, it has much more recently (February 2021) been used in regards to prejudice and discrimination against especially adolescents and children, such as denying them certain rights usually reserved for adults such as the right to vote, run for political office, buy and use alcohol, tobacco, or cannabis, marry, own a gun, gamble, consent or refuse medical treatment, sign contracts, and so forth; indeed, denying them citizenship at all.[5] This can also include ignoring their ideas because they are considered "too young", or assuming that they should behave in certain ways because of their age. The elderly themselves can be deeply ageist, having internalized a lifetime of negative stereotypes about aging.[6] Fear of death and fear of disability and dependence are major causes of ageism; avoiding, segregating, and rejecting older people are coping mechanisms that allow people to avoid thinking about their own mortality.[7]