Drop in on Palm Beach these days, wander around glittering Worth Avenue, and you undoubtedly will get the word. "The Season," someone will say, "certainly is going full force."

Palm Beachers intone the term casually as if its definition is too universally known to explain. First-time visitors may wonder precisely what it means. If your guess is "tourist season," then you should cancel your reservations at The Breakers and head straight for Coney Island.

The Season, as Palm Beachers define it, is the Social Season, a rather specific designation for a rather indeterminate period of time. These days purists mark Thanksgiving as the official starting point and Easter as the end.

It's no surprise that these dates generally correspond with the first snowfall up north, and the first hint of spring thaw. If one does not come to "winter" in Palm Beach between those times, then one is hardly worthy of a listing in the Social Index Directory.

Entry into this little black book is one -- through certainly not the only -- indication that one is "social." The definition of "social" varies with whomever you ask, though "having money," as opposed to "actively earning it," is one generally agreed upon distinction.

For the point is that Palm Beach, founded around the turn of the century as a first-class resort for an emerging class of American millionaires, has still very much maintained the image. Tourists do visit, of course, but a truer definition of The Season is when the rich come home to their comfortable winter roosts.

This annual confluence of weather and wealth touches off a round of parties, galas, teas, soirees and ultra-expensive charity balls. Giving lavish parties is in itself not necessarily important, however. What matters is who comes.

If you do not wish to participate but simply want to observe, that can be arranged. Shopping Worth Avenue, where the price of the diamond necklaces probably surpasses your mortgage, is one way to get to see the pretty people at play. The avenue, in case you don't know, has the reputation as being one of the world's finest (and most expensive) shopping streets, a sort of miniature Fifth Avenue and Rodeo Drive compressed into so few blocks that the Rolls-Royces hardly have a place to park.

If you're of a mind, stop in for lunch at Petite Marmite, Liberace's favorite restaurant and the place where the celebrities seem to like to hang out. Be prepared, of course, to pay dinner prices for lunch. But the food, at last report, is good if not excellent.

The restaurant is one of those places on the island that has its own photographer to make sure the beautiful people don't get away without being caught in the act of having fun. Check the little photo case outside and you'll notice that the late John Lennon, who bought a home in Palm Beach last year, had dinner there with his wife, Yoko Ono, and actor Peter Boyle. l

Wander from the restaurant and saunter east toward the ocean and you'll run into the Esplanade, a two-story collection of saprkling shops which opened only last year. Saks' new store is there, and so is Cartier. Upstairs is Cafe L'Europe, the place to be seen for lunch these days. No wonder. Not only is the place visually all you'd expect of a cozy little European restaurant, but the prices (by Palm Beach standards, at least) are downright reasonable.

If you want lunch there, show up at least half an hour before noon or be prepared to wait 40 minutes.

Besides the shopping, dining and party scene, there are other little diversions that allow you to peek in on how the other half lives, or at least lived.

One is Whitehall, better known as the Henry Morrison Flagler Museum on Coconut Row. This little white palace was built for $4 million in 1901 by Flagler, an associate of John D. Rockefeller, as a wedding present for his second wife and was considered one of the six most magnificent private homes in the world.

The Flaglers lived in the place only two months a year over a mere four years. (The Season, back then, ran from Jan. 1 to March 1, period, and no one worth his social salt would be caught dead on the island after that.) Today, thanks to the largesse of the Flagler family, Whitehall ranks as one of the major (and few) public tourist attractions on the island.

A tour of Palm Beach also would not be complete without a drive along Ocean Boulevard, especially south of Worth Avenue. There, at 720 S. Ocean, you can see the late ex-beatle Lennon's home, next door to the palatial Donahue mansion. (That home once belonged to Woolworth Donahue, heir to the Woolworth dimestore fortune, and recently sold for $3.2 million.)

Just north of the Southern Boulevard bridge, you'll also see the tower of Mar-A-lago, the former home of cereal baroness Marjorie Merriweather Post and the island's largest estate. Until recently, the home belonged to the government but soon will go back to the Post Foundation, which will probably be looking for a buyer. If you've got about $10 million to spend and $1 million a year for maintenance and operation, arrange to see all 115 rooms.

When you run out of mansions going south, you'll know you're out of Palm Beach. So turn around and head north on Ocean Boulevard to the other end of the island (it's only 12 miles from end to end).

Along the way you'll pass the island's most accessible public beach (you'll know you're there when you see the parking meters on the ocean), perhaps the island's only real bargain. At the end of that beach, the road jogs away from the ocean for several miles.

But don't fret. It'll take you in front of the posh Breakers, the island's lavish charity balls and its public cocktail lounge affords one of the few spots on Palm Beach to watch the ocean while you sip your favorite drink.

Just north of the Beach Club and the Palm Beach Country Club, the road rejoins the ocean. If you stay on it until the end, you'll drive past Rose Kennedy's compound. There's no number on the house but it's just beyond 1075 N. Ocean Blvd. Look for a beige garage with servants' quarters above. (You'll probably be disappointed, since most of the estate is hidden from view by a wall. But at least you can say you were there.)

If you keep dirving, you'll soon be out of road but near one of the bestkept secrets on the island. At the tip end of North Ocean Boulevard you'll see a handful of metered parking spaces (parking on side streets and along most of Ocean Boulevard is strictly prohibited. Violators will find their cars ticketed, towed away or both). If one of those spots is open, park and take the short hike northward to the small wooden dock on the Palm Beach Inlet. There you can sit and get a pelican's view of the inlet, where Sundays in The Season look like a continous yacht parade.

If you're really lucky, you'll catch the inlet at high tide, when it fills with azure sea water and turns crystal clear. The view is one money can't buy.