Once people are past middle age, they’re old. That’s how life progresses: You’re young, you’re middle-aged, then you’re old.
Of course, calling someone old is generally not considered polite, because the word, accurate though it might be, is frequently considered pejorative. It’s a label that people tend to shy away from: In 2016, the Marist Poll asked American adults if they thought a 65-year-old qualified as old. Sixty percent of the youngest respondents—those between 18 and 29—said yes, but that percentage declined the older respondents were; only 16 percent of adults 60 or older made the same judgment. It seems that the closer people get to old age themselves, the later they think it starts.
Overall, two-thirds of the Marist Poll respondents considered 65 to be “middle-aged” or even “young.” These classifications are a bit perplexing, given that, well, old age has to start sometime. “I wouldn’t say  is old,” says Susan Jacoby, the author of Never Say Die: The Myth and Marketing of the New Old Age, “but I know it’s not middle age—how many 130-year-olds do you see wandering around?”
The word old, with its connotations of deterioration and obsolescence, doesn’t capture the many different arcs a human life can trace after middle age. This linguistic strain has only gotten more acute as average life spans have grown longer and, especially for wealthier people, healthier. “Older adults now have the most diverse life experiences of any age group,” Ina Jaffe, a reporter at NPR who covers aging, told me in an email. “Some are working, some are retired, some are hitting the gym every day, others suffer with chronic disabilities. Some are traveling around the world, some are raising their grandchildren, and they represent as many as three different generations. There’s no one term that can conjure up that variety.”