People outside this business don't know the kind of heady debates that go on every day inside newsrooms over the usage of words. Sometimes these discussions can get very personal. Such an occasion arose the other day when I used the term "older Americans," in describing the demographic group afflicted with Alzheimer's disease.

My editor changed it to "elderly Americans."

"Elderly?" I protested. "We're talking people 50 years old and up."

"Well," she said, "what's elderly?"

"Not fifty. Fifty's young," I insisted.

The editor, it should be noted here, is closer to 30 than she is to 50.

She asked the city editor what elderly was. He's older than she is. He said over 65. We consulted the dictionary: it said elderly was "somewhat old; past middle age; approaching old age."

Newsrooms are full of anecdotes about young reporters writing stories in which they refer to "middle-aged" men of 34 -- precisely the same age as the editor who is going to read the story and who doesn't think of himself as anywhere near that landmark. Or stories about "elderly men" who are precisely the same age as the managing editor who controls that young reporter's destiny. Managing editors do not think of themselves as elderly. Obviously, some of this business has to do with perspective.

The Census Bureau issued a report on this subject last week and the Associated Press account of it read thusly: "The nation's median age has topped 31, with the middle-aged and the very old becoming the fastest-growing segments of society . . . .

"The median age as of last July 1 was estimated at 31.2 years, meaning that half of all Americans were older than that and half younger.

" 'The median age has increased each year since 1971, when it was 27.9 years. This aging trend is expected to continue as the early baby boom generations head toward middle age,' the bureau said."

The census report found that the 35-to-44-years-old age group increased 19.5 percent and the number of Americans 85 years old and older grew 19.4 percent. The 75-to-84-years-old age group increased by 11.5 percent and the 25-to-34-year-old group increased by 10.5 percent.

Louisa Miller, a statistician and demographer at the Census Bureau who wrote the report, says the bureau considers people 65 and older to be senior citizens, but that it doesn't have official specifications for other groups.

"We don't really have an official middle age," she says. "I would tend to think of it as 35 to 64." Pause. "Maybe even 40 to 64." Forty?

This was, she says, a personal opinion that she was discovering was subject to rapid change.

"The very old might be 85 and older," she says. There had been discussions about putting people 75 years old in that group. "But people 75 and older don't seem so old to me.

"I used to think middle age was younger, but as I get older . . . You have to be careful what you say middle-aged is," she says. "I just think the perception is different. As more of the population gets older, you don't see yourself as older. People act younger, too."

Clearly, with the new demographics, it is time for this aging business to get redefined.

First off, I'm not sure the term elderly is of much use. I have the good fortune to know two people nearing their middle eighties who are a great deal younger in mind and spirit than some of my contemporaries (and never mind what group we're talking about here). I humbly submit that the term "older," which carries a note of accomplishment, be substituted for "elderly," which evokes images of canes, rasping voices and cracking minds. Older has a certain mystique about it, as in "older man" or, for the followers of Joan Collins' adventures, "older woman."

Which brings us back to the thornier problem of what is middle-aged? I used to think of middle age as anywhere between 40 and 60, but I am having the same second thoughts on this as Louisa Miller. Middle-aged meant you had a mortgage and a midriff, but most of the people I know who are in their forties don't have midriffs and a lot of them lost their mortgages during divorces.

Looking at it another way, there is no question in my mind that people in their thirties are still young. A lot of them think of themselves as too young to marry or have children. That means they are definitely nowhere near middle age. And there is no question in my mind that people in their fifties and sixties are not old. So they could probably be considered middle-aged.

But people in their forties?

Middle-aged?

That, as I said, is a matter of perspective. And they seem to be getting younger all the time.