You know the term, “He wears more than one hat”?

That’s me.

The other day I was heading downtown and, as usual, put on my slightly faded Mets cap — basic black with interlocking orange “N” and “Y,” nothing flat-billed or fancy — and then remembered that I wanted to keep another in the car as a spare.

Sensible skin care demands covering up, especially if hair has been AWOL since circa 1985. In summer, I rarely wear shorts. I favor long sleeve shirts no matter the temperature. Out for my daily 3-mile walk, I apply suntan lotion like Spackle on Sheetrock.

Prudence pays off. A while back the dermatologist told me: “For someone up there like you, I’ve never seen so few spots.” I prefer to overlook the “up there” crack and celebrate the doctor’s assessment that, so far, I do not resemble a camouflage tent.

In any event, as I was leaving the house with a few pieces of mail and a DVD due at the library, I put the second hat atop the first for convenience, intending, of course, to remove it before driving off.

Around downtown I went: to the library where I looked for other movies to borrow — mysteries, political intrigue, suspense, and anything with Helen Mirren, the “it” girl of the older set — and then to the cleaner where my beloved ratty black sweater was being repaired. I went to the post office and bought books of the beautiful new stamps recalling Depression-era posters and then stopped at the supermarket.

Ahead of me, a customer chatted amiably with the checkout clerk. They exchanged pleasantries and parted in familiar fashion.

“Have a great day,” said the clerk.

“You, too,” replied the customer.

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I put my items on the conveyor — blueberries for brain power and yogurt for enzymes — and said hello to the young woman at the register.

No more than 18 or 19, she looked at me in what seemed peculiar fashion.

“H’lo,” said the clerk, quickly scanning the berries and Chobani, and glancing up again.

“Nice day,” I said.

“Uh-huh,” said the clerk, risking another look.

I paid, took my change, and tried for an upbeat ending.

“Have a good afternoon,” I said.

Eyes again fixed above my forehead, the clerk said something — maybe it was “you, too,” or maybe not — and then, with renewed cheerfulness, greeted the next shopper.

In the driveway, I gathered up my stuff and opened the front door. I put down the sweater, the stamps, the supermarket bag. I took off my hat.

But wait . . . what was this? The hat was not one, but two.

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On top of the Mets cap was another — the spare I had never taken off. Without intending, I had turned myself into a millinery short stack. I stared at the hats, the first nestled inside the second. No doubt about it: One plus one is two.

For some reason best determined by a therapist should I ever go that route, all this seemed hilarious to me — absolutely smashing. Alone in the house, I began laughing. I looked in the mirror. I put both hats back on. I posed. How stylish!

I thought of myself parading around for more than an hour giving onlookers the idea that this is how I ordinarily dress. If you present yourself in unabashed twin peaks fashion to the library staff or dry cleaner and say nothing about it, the intention is clear — there is no error, I wear two hats. Don’t you?

Now I see that the young supermarket clerk was not being coarse or distant. Accustomed to shoppers choosing the old one-lid look, she simply wondered what might explain the fashion breakthrough before her. When I said, “Good afternoon,” perhaps she was beginning to say, “Right-on, Dad. Looking good.”

None of this amounts to another of those laments about memory loss and inevitable decline. Yes, big deal, sometimes I walk from first floor to second with an urgent mission in mind only to go blank at the top of the stairs. In the shower, I have trouble remembering if I washed between my toes. And, OK, the other day I found myself staring at a paper cup and wondering if I had taken a cholesterol pill the moment before. But there is no reason to panic.

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A multiple headwear event might happen at any age. That’s my official statement. To be safe, I plan to eat more blueberries, check the mirror whenever leaving the house and hope that, just maybe, Helen Mirren digs guys who wear two hats.