“East of Broadway is NoLIta, until the Bowery. It goes down to Canal Street, and starts at Houston,” Michael Pandolfo said, giving the borders of the area in Manhattan more and more frequently referred to by a contraction of North of Little Italy.

Mr. Pandolfo said this while sitting with his friends and co-workers in Nolita House, a two-and-a-half-year-old restaurant and pub on Houston Street, which stands across the street from SoHo Billiards. How an establishment on the northern side of Houston can take the neighborhood name for the area that is South of Houston is a point to ponder.

Another might be, where exactly is NoLIta?

Around the bend from Nolita House, down Mott Street, going south, is an apartment building called SoHo Abbey. And one block down from the restaurant is another apartment building, SoHo Court (also, improbably, on the northern side of Houston).

Do these names belie Nolita House’s moniker? There’s no NoLIta on the Web site of New York City’s Department of City Planning, which lists 290 total neighborhood names in all of New York City, and 39 in Manhattan. You also won’t find NoLIta on the subway map or on the maps in the back of taxis.

However, the maps found in IN New York magazine, the Manhattan hotel staple, do list them. “We endeavor to be as detailed as possible,” the magazine’s marketing director, George Wilson, said. Several other tourist maps also carve out a small region for NoLIta. As does Zagat Survey, whose borders of NoLIta concur with Mr. Pandolfo’s for the Bowery and Houston Street, but not for the western and southern boundaries. (Zagat Survey has Lafayette Street and Kenmare Street, respectively.)

Even among Mr. Pandolfo’s group in NoLIta House a consensus could not be reached. While Mr. Pandolfo, the owner of a music production company called Wonderful, said that NoLIta has been around for about 10 years, Vlad Gutkovitch, at the time an intern who was having lunch with his boss, said he has been working or going to school in the area for seven years on and off, and he’s “never heard of NoLIta until this conversation.”

So who gets to determine a neighborhood’s name? In America in general, and in New York City in particular, there’s no such thing as definite neighborhood boundaries, a professor of history at Columbia University and editor of the Encyclopedia of New York City, Kenneth T. Jackson, said. Therefore, the post office, the police department, the fire department, and anyone else who bothers to keep track of neighborhoods all have a different set of divisions. He contrasted this with Berlin, where there are official boundaries of every neighborhood. Because of its diverse ethnic groups, America is different, Mr. Jackson said.

He noted that the subdividing of neighborhoods in New York City made sense. “Technically Harlem is bigger than most American cities,” he said. “To call everything north of 96th Street by one name is not very helpful.”

The main drivers for many of the neighborhood names are real estate agents, the historian said. “A desire to make a neighborhood seem smaller, to cut out a piece of a neighborhood and give it some cache,” he said. “The meatpacking district is now a very trendy neighborhood. It used to be just a couple of blocks of meatpackers.”

While the arbiters of trendy play a role in deciding which name is in and which is out, the decisions of map makers are integral to which neighborhoods you’ll see over and over again.

Stephan Van Dam, president of the mapmaking VanDam Inc., said that while many sources come up with neighborhood names — from real estate agents to city agencies to landmarks and historical decisions — mapmakers make it visual. He added that sometimes mapmakers add new names, following a centuries-old history of name-designating cartographers.

John Tauranac, a New York University professor who was the chief designer of the 1979 subway map, which dramatically updated the map from previous versions and is the basis of today’s map, said the decision of which neighborhoods to include was “pragmatic at best.”

“Defining your neighborhood is a personal matter that is generally more visceral than intellectually and historically accurate,” Mr. Tauranac writes in his street atlas book, Manhattan Block by Block.”Your neighborhood is usually defined as being about as far as you can schlep a shopping cart.”

So where do the names come from? “Driven by real estate market quite frankly,” Mr. Tauranac said. “I’m convinced that they are products of real estate lobby.” As an example, he cited the area in Manhattan between 42nd and 59th streets, and Eighth Avenue to the Hudson River. “I still call it Hell’s Kitchen. But real estate people call it Clinton.” The name improvement is obvious.

Messrs. Jackson and Tauranac were two of many academics, mapmakers, and others interviewed for this article who said real estate agents are the main stimulators of neighborhood names.

“I don’t know if it’s accurate to say real estate brokers create the names,” a senior vice president for the real estate company Prudential Douglas Elliman, Corinne Pulitzer, said. “We drive the names.”

She said that after neighborhoods becomes hot, the real estate agents pick up on it and market them — which happened in the meatpacking district, NoHo and NoLIta. “We don’t do the christening, we do the marketing.”

Davida Maron, a broker for Century 21 Kevin B. Brown & Associates, agreed. “Real estate agents are very influential and do have a way of helping to brand a neighborhood. But that’s probably an exception, not a rule.”

And a senior vice president at Kevin B. Brown, Sue Marcus, said that in her 28 years of working in real estate, she has “never heard of a real estate agent starting a neighborhood name.”Some real estate agents, however, pointed to DUMBO (Down Under the Manhattan Bridge Overpass) as an example of developers coining the name to coincide with their marketing of a new housing development in the late 1990s.

Still, most names start elsewhere. A senior vice president of the Real Estate Board of New York, Michael Flattery, said neighborhood names developed organically. “Names for neighborhoods tend to emerge from the neighborhoods themselves,” he said.

The CEO of the development and consulting firm, the Brody Group, Eric Brody, said neighborhood names come from a variety of places. “Some are geographical or based on historical landmarks,” he said. He gave Park Slope — because it slopes against Prospect Park — and DUMBO based on the Manhattan Bridge, as examples.

“Some people perceive a negative stigma attached to Harlem,” said David Owens, a real estate agent “and they’re possibly trying to soften name.” Mr. Owens has just finished developing and selling five condominiums at 394 Manhattan Ave., on 117th Street, for Halstead Property.

In addition to removing a stigma, Mr. Owens said developers may change the names of areas, or at least cling to existing alternative names, in order to justify the prices they’re asking. Or, they might subdivide a neighborhood simply “to remove the largeness from it.”

“New York City is very block sensitive — almost building sensitive,” Mr. Owens said. “One building is a $10 million brownstone, and the next building is rent controlled. Property value changes building to building, also block to block.”

Some residents where the new condominiums are located have called the area Morningside Heights or Hudson Heights, but not Mr. Owens. “I keep it real and say it’s in Harlem,” he said. The advertisements that Halstead used to promote the condominiums avoided the issue altogether.”SoHo Living Uptown,” they promised.

Neighborhood names don’t just spring up, they shift around. The co-author of “Brooklyn by Name: How Neighborhoods, Streets, Parks, Bridges, and More Got Their Names,”Leonard Benardo, said neighborhood boundaries are “malleable.”For example, in the last several decades, Chinatown has been ballooning over to the east. “It’s all open to interpretation,” he said.

A historian and author of “Touring the Flatiron: Walks in Four Historic Neighborhoods,” Joyce Mendelsohn, said that the Lower East Side was once the name for everything as far uptown as East 14th Street, and technically still is, but the area between Houston and 14th streets is now almost universally known as the East Village, and that designation is beginning to drip into the streets south of Houston Street, as well. “East Village is jumping over Houston Street so quickly,” she said.

In any case nobody is keeping official score of which blocks fall under which neighborhood name. But some think that if there does exist some official list of neighborhoods, then the Department of City Planning has it. The department’s director of population division, Joseph Salvo, set the record straight. He called their list just a tool, emphasizing that it was merely “subjective” and “not comprehensive”

“It took us about 10 months of research, community contact, work with borough offices, borough presidents, in effort to come up with something we felt would be a good public tool,” Mr. Salvo said about the map the department put together in the late 1980s, called “New York: A City of Neighborhoods.” He added that they also used historical references.

Some city residents have creative neologisms for their home neighborhoods. Marc Matyas, co-owner of Nolita House, said he lives in the Chillage, “not Chelsea, not the Village — the Chillage.”

Chillage might just be in the making. Mr. Jackson predicted that we will see more neighborhood names in the future. “There’s room for more,” he said. “Most small cities don’t have that many people, and they have neighborhoods.”