It may be considered as a familiar and sometimes endearing appellation.

An Irishwoman calls her husband "the old man," and he returns the caressing expression by speaking of her as "the old woman." But now, said he, just suppose a case like one of these.
A young stranger is overheard talking of you as a very nice old gentleman.

A friendly and genial critic speaks of your green old age as illustrating the truth of some axiom you had uttered with reference to that period of life.

What _I_ call an old man is a person with a smooth, shining crown and a fringe of scattered white hairs, seen in the streets on sunshiny days, stooping as he walks, bearing a cane, moving cautiously and slowly; telling old stories, smiling at present follies, living in a narrow world of dry habits; one that remains waking when others have dropped asleep, and keeps a little night-lamp-flame of life burning year after year, if the lamp is not upset, and there is only a careful hand held round it to prevent the puffs of wind from blowing the flame out.

That's what I call an old man.
Now, said the Professor, you don't mean to tell me that I have got to that yet?
Why, bless you, I am several years short of the time when--[I knew what was coming, and could hardly keep from laughing; twenty years ago he used to quote it as one of those absurd speeches men of genius will make, and now he is going to argue from it]--several years short of the time when Balzac says that men are -- most--you know--dangerous to--the hearts of--in short, most to be dreaded by duennas that have charge of susceptible females .-- What age is that?
said I, statistically .-- Fifty-two years, answered the Professor .-- Balzac ought to know, said I, if it is true that Goethe said of him that each of his stories must have been dug out of a woman's heart.