You know what a hotel is, of course. And perhaps, a condominium - a residential building divided into separate units that are owned by different people.

What you may not know is that in some U.S. cities, the two have come together into something called a "condo hotel."

Several can now be found in beach and mountain resort towns and a few modest-sized cities.

However, none is more famous than the legendary, 105-year-old Plaza Hotel in New York, on glitzy Fifth Avenue across from Central Park.

The Plaza closed for renovation in 2005. When it reopened two years later, more than half of it had been transformed into one of these trendy condo hotels. The posh and historic Hotel Del Coronado, on the Pacific Ocean near San Diego, California, did much the same thing.

Here's how it works: You buy - not rent - what amounts to an apartment or suite. If it's at The Plaza, it will cost you between $1.5 million and $9 million. 

But hey, New York's expensive, right?

The Plaza Hotel in New York sells trendy condo units, but owners can stay there no more than 120 days a year. 

The rest of the time, the hotel's reservation folks can book guests into your place, just as they would in the regular hotel’s rooms. They lock anything of yours that’s priceless or personal in a closet when others are staying there.

The good news for you is that whatever Mr. Conklin from Cleveland and Ms. Dow from Denver pay to stay in your suite - and presumably it would be a top rate for such nice accommodations - goes to you, minus housekeeping charges and a management fee. 

So if you're lucky - and rich -you can now live in really special quarters up to one-third of the year, while others pay off your mortgage the rest of the year.

You cannot furnish it with your grandfather’s rocking chair, iridescent paintings of elephants, or your beer-can collection, though - or anything else that might turn off paying guests.

The hotel picks the furnishings and the bath towels. 

So far, according to the USA Today newspaper, a great many of the nation’s condo-hotel units have been purchased not by rich individuals but by richer corporations, including foreign ones, that want a nice place for their executives to stay when they’re in town or working late at the office.