Some neighborhood names appear to be jokes. Some have stuck around for centuries, despite changing connotations. Some shift with the winds of gentrification. Welcome to Blurred Lines, in which writer Keith Williams of The Weekly Nabe studies New York City's changing neighborhood boundaries.

By most definitions, the Triangle Below Canal Street is really more of a trapezoida trapezius, if you want to get technical about it. Perhaps that's why residents were unhappy with the acronym Tribeca when it became the name of choice in the 1970s. Or, perhaps they were upset by the misappropriation of the name. According to Sean Sweeney, director of the SoHo Alliance, "triangle below Canal" was used by a community group on Lispenard Street between Church and Broadway to describe its block, which actually does resemble a triangle. Then the Times got hold of the name and applied it liberally, helping to solidify Manhattan's second abbreviated neighborhood (Soho was the first).

It's now one of the priciest neighborhoods in the city, but Mr. Sweeney recalled an occurrence 50 years ago that defined its old character. He was a freshman in college, walking down one of the local streets with a friend; a police cruiser tailed them, suspicious of what they were doing. "It was deserted at night," he said. "There wasn't a single human being on the street."

By the mid-1970s, Tribeca had become a haven for artists, but they would soon be pushed out by rising rents and a lack of protections (now known as "loft laws"). This purge would lead directly to the infamous naming of Dumbo.

The boundaries of Tribecathe large versionhave changed little in the interceding 40 years: the Hudson River, Canal Street, and Broadway usually form three sides. The biggest debate is where the southern edge transforms into the Financial District. Is it at Vesey? Murray? Chambers? Often the border is pushed by new developments wanting to claim posh Tribeca as their locale, rather than the Financial District.

30 Park Place, on the corner of Church Street is one property residing in this gray zone. Curbed historically placed it in FiDi, but when the building launched sales, it was marketed as Tribeca. Listings website StreetEasy also locates it within Tribeca.

While these borders are open to debate, for now, certain ones are not: Tribeca has had five historic districts assigned to it. The first four came in 1991 and 1992; parts of two blocks were added in 2002. Some of the lines are jagged, possibly because certain property owners wanted to be excluded from the designation.

In part because one historic district extends east of Broadway, Mr. Sweeney sees Broadway as insufficient to define the area. A recent push by the group Tribeca Trust to expand the protected zone adds a few blocks to the northeast section of the neighborhood, all the way to Centre Street.

Locals had some other suggestions for the moniker of their own neighborhood. Let's take a look at a few.

Lower Hudson: Named not for the River, but the Street. The term had been around since 1865, when Marcus Ormsbee took a photo of some of the shops at where Hudson Street rises from the junction of Chambers Street and West Broadway.

Lo Cal: This appeared in a single Times article, from 1976, and just as quickly disappeared. Google searches were frustrating, yielding lots of hits about "lo cal newspapers" (the space a text-recognition error) and "lo-cal yogurt."

Washington Market: Once New York's most important wholesale produce market, it relocated to Hunts Point Terminal in the Bronx in the 1960s. It dates from the early 19th century; Jonathan Zalman recounted its storied (and dirty) history for Narratively last year.

SoSo: An adaptation of South of SoHo. Not the most inspiring namealthough to some in the 1970s, "so-so" might have been an oversell.

Lower West Side: A counterpart to the Lower East Side, which had started to take its own identity around the same time. This is Mr. Sweeney's preferred nomenclature.

Lower Manhattan Mixed-Use District: The official designation for the area in 1976, when the city rezoned 62 blocks. Not only is this a mouthful, it's generally wise to refrain from any name that could be used pejorativelyin this case, MUD.

An earlier version of this post stated the original area of Tribeca was two blocks wide. It was only one block wide.

· Blurred Lines archives [Curbed]