Weekly Tips: No.3
"Elderly" and "youth": How should we refer to older and younger people?

A.
Older people

Common nouns for referring to older people are:

an old person; an elderly person; a senior citizen
old people; elderly people; the old; the elderly; senior citizens

Note that "the elderly" and "the old" are plural nouns. "The elderly" is more polite than "the old".

The elderly are normally seen as vulnerable members of society.

Elder is a noun, but what does it mean? Check! Here are two examples of its use.

In a traditional society, important issues are often decided by the elders of a community.
Young people do not pay enough attention to the wisdom of their elders.

"Elder" is NOT used to refer to older people in a general sense.

To refer to the state of being old, we use "age" or "old age".

In traditional societies age is associated with experience and old people therefore play an important role in the community.

B
Younger people

Common nouns for referring to younger people are:

a young person; a youth; a teenager; an adolescent
young people; youths; teenagers; adolescents; the young; the youth

Note that a youth/youths refers to young men only, and often involves the idea of anti-social behavior.

The police assumed that the youth had stolen the computer just because of his age and the clothes that he was wearing.
(Note that here, "age" just means "the number of years that someone has lived".)
In some areas of the city, older people are in danger of being attacked by gangs of youths.

"The youth", as a plural noun, refers to young people in general. When it does so, it is normally in a phrase such as "the youth of Japan" or "the youth of today" since it is used to describe young people of a particular area or time.

"The young" is also a plural noun that is used to refer to young people in general, but in this case it is young people as opposed to older people.

The mobile phone was developed as a device for businessmen, but in fact it first became popular among the young.
When mobile phones were first put on the market, they quickly became popular among the youth of the time.

To refer to the state of being young, we use "youth".

The older I get, the more I agree with that famous saying, "Youth is wasted on the young".